footer {
  margin: 0 auto;
  max-width: 1920px;
  position: relative;
}

footer .row {
  --bs-gutter-x: 1.5rem;
  --bs-gutter-y: 0;
  display: flex;
  flex-wrap: wrap;
  margin-top: calc(var(--bs-gutter-y) * -1);
  margin-right: calc(var(--bs-gutter-x) * -.5);
  margin-left: calc(var(--bs-gutter-x) * -.5);
}

footer .up-arrow {
  background-color: #082340;
  border-radius: 50%;
  cursor: pointer;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  height: 65px;
  position: absolute;
  right: 3%;
  top: 12%;
  width: 65px;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
}

@media screen and (max-width: 768px) {
  footer .up-arrow {
    display: none;
  }
}

footer .up-arrow span {
  color: #fff;
  font-size: 1.5rem;
  -webkit-transform: translateY(5px);
  transform: translateY(5px);
}

footer .f-blue,
footer .f-white {
  padding: 3rem 1.9rem;
}

@media screen and (max-width: 768px) {
  footer .f-blue,
  footer .f-white {
    padding: 2rem 25px;
  }

  footer .f-white .f-col2 {
    display: none;
  }
}

footer .f-blue {
  background-color: #082340;
  background-position: 100% 100%;
  background-repeat: no-repeat;
  color: #fff;
}

@media screen and (max-width: 768px) {
  footer .f-blue .row:first-child {
    border-bottom: 1px solid #787a7a;
  }

  footer .f-blue .row:nth-child(2) {
    padding-top: 2rem;
  }
}

footer .f-blue a,
footer .f-blue li {
  color: inherit;
  font-size: clamp(16px, 1.04vw, 20px);
  line-height: 1.5;
}

@media screen and (max-width: 768px) {
  footer .f-blue a,
  footer .f-blue li {
    font-size: 1rem;
  }
}

footer .f-blue .f-col1 ul {
  padding: 0;
}

footer .f-blue .f-col1 ul li:first-child,
footer .f-blue .f-col1 ul li:nth-child(4) {
  margin-bottom: 1rem;
}

footer .f-blue .f-col2 .useful-links {
  display: none;
  margin-bottom: 1rem;
  -webkit-box-pack: justify;
  -ms-flex-pack: justify;
  justify-content: space-between;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  cursor: pointer;
}

@media screen and (max-width: 768px) {
  footer .f-blue .f-col2 .useful-links {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
  }
}

footer .f-blue .f-col2 .useful-links .arrow-icon,
footer .f-blue .f-col2 .useful-links span:nth-child(2) {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  height: 20px;
  width: 20px;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  -webkit-transform: rotate(0deg);
  transform: rotate(0deg);
  -webkit-transition: -webkit-transform 0.3s ease;
  transition: transform 0.3s ease;
}

footer .f-blue .f-col2 .useful-links .arrow-icon svg,
footer .f-blue .f-col2 .useful-links span:nth-child(2) svg {
  height: 1rem;
  width: 1rem;
}

footer .f-blue .f-col2 .useful-links.active .arrow-icon,
footer .f-blue .f-col2 .useful-links.active span:nth-child(2) {
  -webkit-transform: rotate(180deg);
  transform: rotate(180deg);
}

footer .f-blue .f-col2 ul {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -ms-flex-wrap: wrap;
  flex-wrap: wrap;
  padding: 0;
}

footer .f-blue .f-col2 ul li {
  -webkit-box-flex: 50%;
  -ms-flex: 50%;
  flex: 50%;
  margin-bottom: 10px;
}

@media screen and (max-width: 768px) {
  footer .f-blue .f-col2 .f-menu3 {
    display: none;
    width: 100%;
    padding: 0;
    margin: 0;
  }

  footer .f-blue .f-col2 .f-menu3.open {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-wrap: wrap;
    flex-wrap: wrap;
    margin-top: 0.5rem;
  }

  footer .f-blue .f-col2 ul li {
    -webkit-box-flex: 100%;
    -ms-flex: 100%;
    flex: 100%;
    padding: .5rem 1rem;
  }
}

footer .f-blue .f-col3 ul:first-child {
  margin-bottom: 10px;
}

@media screen and (max-width: 768px) {
  footer .f-blue .f-col3 ul:first-child {
    display: none;
  }
}

footer .f-blue .f-col3 .social-icons {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  gap: 10px;
}

@media screen and (max-width: 768px) {
  footer .f-blue .f-col3 .social-icons {
    padding-left: 0;
  }
}

footer .f-blue .f-col3 .social-icons li .svg-circle {
  border: 1px solid #fff;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  height: 40px;
  width: 40px;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  border-radius: 50%;
  justify-content: center;
}

footer .f-blue .f-col3 .social-icons li .svg-circle svg {
  height: 24px;
  width: 24px;
}

footer .f-blue .f-col3 .social-icons li:first-child .svg-circle svg,
footer .f-blue .f-col3 .social-icons li:nth-child(2) .svg-circle svg {
  height: 20px;
  width: 20px;
}

footer .f-col1 {
  width: 42%;
}

@media screen and (max-width: 1360px) {
  footer .f-col1 {
    width: 35%;
  }
}

@media screen and (max-width: 768px) {
  footer .f-col1 {
    width: 100%;
  }
}

footer .f-col2 {
  width: 37%;
}

@media screen and (max-width: 1360px) {
  footer .f-col2 {
    width: 40%;
  }
}

@media screen and (max-width: 768px) {
  footer .f-col2 {
    width: 100%;
  }
}

footer .f-col2 .f-menu div {
  float: left;
  padding-bottom: 4rem;
  width: 50%;
}

footer .f-col2 .f-menu div:nth-child(3) {
  padding-bottom: 0;
}

footer .f-col2 .f-menu div p {
  font-size: clamp(18px, 1.25vw, 24px);
  line-height: 1.2;
  margin-bottom: 15px;
}

footer .f-col2 .f-menu div span {
  display: block;
  font-size: clamp(16px, 1.04vw, 20px);
  width: 100%;
}

footer .f-col2 .f-menu div a {
  font-size: clamp(16px, 1.04vw, 20px);
  font-weight: 500;
  text-decoration: none;
  width: -webkit-fit-content;
  width: -moz-fit-content;
  width: fit-content;
}

@media screen and (max-width: 768px) {
  footer .f-col2 .f-menu div a {
    font-size: 1rem;
  }
}

footer .f-col3 {
  width: 21%;
}

@media screen and (max-width: 1360px) {
  footer .f-col3 {
    width: 25%;
  }
}

@media screen and (max-width: 768px) {
  footer .f-col3 {
    border-top: 1px solid #787a7a;
    padding-top: 1rem;
    width: 100%;
  }
}

footer .f-col3 .f-menu2 {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -ms-flex-direction: column;
  flex-direction: column;
  position: relative;
}

footer .f-col3 .f-menu2:before {
  background-color: #000;
  content: "";
  display: block;
  height: 100%;
  left: -20px;
  position: absolute;
  top: 0;
  width: 1px;
}

@media screen and (max-width: 768px) {
  footer .f-col3 .f-menu2:before {
    display: none;
  }

  footer .f-col3 .f-menu2 {
    -webkit-box-orient: vertical;
    -webkit-box-direction: reverse;
    -ms-flex-direction: column-reverse;
    flex-direction: column-reverse;
  }
}

footer .f-col3 .f-menu2 ul {
  padding-left: 2rem;
  -webkit-box-flex: 100%;
  -ms-flex: 100%;
  flex: 100%;
  margin-bottom: 0;
}

@media screen and (max-width: 768px) {
  footer .f-col3 .f-menu2 ul {
    padding-left: 0;
  }

  footer .f-col3 .f-menu2 ul li {
    padding: .5rem 0;
  }

  footer .f-col3 .f-menu2 ul:first-child {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-wrap: wrap;
    flex-wrap: wrap;
  }

  footer .f-col3 .f-menu2 ul:first-child li {
    -webkit-box-flex: 50%;
    -ms-flex: 50%;
    flex: 50%;
  }
}

footer .f-col3 .f-menu2 ul:nth-child(2) li {
  margin-bottom: 0;
}

@media screen and (max-width: 768px) {
  footer .f-col3 .f-menu2 ul:nth-child(2) {
    margin-bottom: 1.5rem;
  }

  footer .f-col3 .f-menu2 ul:nth-child(2) li {
    margin-bottom: 10px;
  }

  footer .f-col3 .f-menu2 ul:nth-child(2) li a {
    font-size: 2rem;
    font-weight: 600;
  }
}

footer .f-col3 .f-menu2 ul li a {
  font-size: clamp(16px, 1.14vw, 22px);
}

@media screen and (max-width: 768px) {
  footer .f-col3 .f-menu2 ul li a {
    font-size: 1rem;
  }
}

footer .f-col3 .f-menu2 ul li .m-show {
  display: none;
}

footer .f-col3 .f-menu2 li {
  margin-bottom: 10px;
}

footer .engage-txt {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  font-size: clamp(50px, 5.52vw, 106px);
  font-weight: 500;
  height: 100%;
  line-height: 1;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -ms-flex-direction: column;
  flex-direction: column;
}

@media screen and (max-width: 768px) {
  footer .engage-txt {
    -webkit-box-orient: horizontal;
    -webkit-box-direction: normal;
    -ms-flex-direction: row;
    flex-direction: row;
    padding-bottom: 1.5rem;
  }
}

footer .engage-txt span:nth-child(2) {
  color: #f15b40;
  margin-top: -.88rem;
}

@media screen and (max-width: 768px) {
  footer .engage-txt span:nth-child(2) {
    margin-top: 0;
  }
}

footer .f-col2 .f-menu div p {
  max-width: 300px;
}

hr.footer-sect-ts {
  margin-top: clamp(30px, 8vh, 130px);
}

/* =========================================
   EFFECT UNDERLINE DESKTOP - USEFUL LINKS
========================================= */
@media screen and (min-width: 769px) {

  footer .f-blue .f-col2 .f-menu3 li a {
    position: relative;
    display: inline-block;
    text-decoration: none;
    padding-bottom: 2px;
  }

  footer .f-blue .f-col2 .f-menu3 li a::after {
    content: "";
    position: absolute;
    left: 0;
    bottom: -3px;
    width: 100%;
    height: 1px;
    background-color: currentColor;

    /* linea visibile di default */
    transform: scaleX(1);

    /* la linea si ritira verso destra */
    transform-origin: right;

    transition: transform 0.35s linear;
  }

  footer .f-blue .f-col2 .f-menu3 li a:hover::after {
    /* scompare da destra verso sinistra */
    transform: scaleX(0);
    transform-origin: right;
  }

}
Come funziona

Stato normale:

linea completamente visibile

Hover:

la linea si ritira da destra verso sinistra
scompare con animazione lineare

Quando togli il mouse:

torna visibile
Se vuoi effetto più premium

Ti consiglio questa versione leggermente più elegante:

height: 2px;
bottom: -4px;
transition: transform 0.4s ease;

risultato più moderno.

Se vuoi, posso aiutarti a fare lo stesso effetto anche per i social o gli altri link del footer mantenendo coerenza visiva del sito.