Upon re-reading your question, I've realised it might not be the add-ons you are referring to but instead the actual Toolbar. I've had this happen to me before too on both Mac & Windows, frustrating behaviour. I suspect the problem might be caused by an accidental keyboard-shortcut used.

The answer might be as simple as getting out of full-screen mode and checking the options.

Here's some things to try:
What happened to the File, Edit, and View menus? (Firefox support)

How to unhide titlebar, tabs, and bookmarks toolbar? (Firefox support)

where is tools drop down menu, it's not on my Firefox menu (Firefox support)

https://www.wikihow.com/Get-Hidden-B...-Toolbars-Back

There is also an option under Firefox's View menu for Toolbars. It might depend upon which overall Firefox layout view you choose, classic or modern perplexing lol.