try inserting the CSS on Appearance > Customizer > Additional CSS

I checked, and it appears this is a standard submenu dropdown from JetMenu. That means the behavior would be the same regardless of what you place inside the dropdown, not only WPML. The following CSS controls the width:

.jet-mega-menu.jet-mega-menu--layout-horizontal .jet-mega-menu-sub-menu {    position: absolute;    top: 10%;    min-width: 200px;    z-index: 998;}

You can adjust the min-width to any value you prefer. However, keep in mind that this will affect all submenu items. If you want to target only this specific menu item, you can use its ID: jet-mega-menu-item-wpml-ls-52-en.