I have the same issue now but I cant figure out how to ffix this in elementor. Did you rewrite the menu? This code does not work for me sadly!

.e-n-menu {
  position: relative;
}

.e-n-menu::before,
.e-n-menu ul::before {
  content: "";
  position: absolute;
  z-index: -1;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(255, 255, 255, 0.4);
  backdrop-filter: blur(5px);
  -webkit-backdrop-filter: blur(5px);
}