We just need some way to run ‘unpopular’ but personally-important addons: a hidden pref, or a permission.
Or allow sideloading. I described my use case for wanting this here: https://github.com/mozilla-mobile/fenix/issues/11308#issuecomment-662877387
Another suggestion: put small simple auto-approved addons like mine in a category, like ‘experimental’, so they don’t show up in an AMO search and are limited to 50 installs.
I’ve used Fennec since it was released on Maemo on the Mokia N810. Most of my addons started life as userscripts and userstyles. Web Extensions enabled me to distribute those more easily - most of my users were too untechy to manage Greasemonkey and Stylish. But if you persist in disallowing personal addons can you at least provide a userscript and userstyle manager as approved addons? They don’t have to be fully-featured (as long as I can use localStorage). Then I could wind the clock back and get 80% of what I have now.