Currently, on Special:EditWatchlist, you must manually select every entry you wish to remove from your watchlist. This makes it very tedious if you want to remove all or almost all of the entries. You can work around this by using the raw version of Special:EditWatchlist or shift-clicking on the list, but these are hard to discover.
Instead, it would be helpful to have an explicit option to select all the entries at once.
This request received 16 votes during the 2023 Community Wishlist Survey.