Yes, mobile Firefox was great until version ~60 something. You could install all the extensions from the store. But now there's like only 18 extensions for mobile.

But there is another way to organize bookmarks like one would expect.

_shameless plug_

You can use Websktop webapp for this. That way you'll have a fully customizable grid of bookmarks. It could look like this:

https://i.ibb.co/5T3pnXH/mobile.png

editing and creating bookmarks, as well as organising them into folders, as well as opening multiple bookmarks/folders simultaneously and bookmarking multiple tabs at the same time all work fine for me on Firefox on Android

Weird. I have a single "Bookmarks" menu item. Opening that shows them. I can tap to open, or "X" to delete. Long-press to select (multiple) which reveals a share icon and a triple-dot with open, open in private or delete. That's it. There is no edit or move operation.

(I noticed adding to a folder appends, and for a while was carefully shuffling between folders to sort, then realized they'd given up on bookmarks so I should too.)