uBlock Origin is one of the 18 extensions that are pre-approved for use in Firefox for Android. To use any other add-ons from addons.mozilla.org, you'll need to use Firefox Nightly (https://play.google.com/store/apps/details?id=org.mozilla.fe...) and follow these instructions:
I'm not sure why Mozilla is refusing to allow these extensions on the Beta channel, since the WebExtensions support is definitely stable enough for Firefox Beta.
I'm not sure why companies think that restricting usage this way improves their product in any way. You need a different build, and an online account to do something that should require neither.
Heck, I can only partially understand the "click many times over crap" to enable experimental features, which should have been _enough_ to begin with (and certainly not a requirement in a beta build). How many hoops do I need?
After reading this, I was really /hoping/ Fennec would remove the requirement of having a Mozilla account, but no, you still need to create an account and an useless "collection".
TBH I use (and ever used) Firefox just due to the available extensions. The value proposition has decreased quite a bit with recent FF versions, and on Android uBlock is pretty much the only reason I stick to it.
I wish I had more alternatives, because clearly the browser duopoly isn't working.
https://blog.mozilla.org/addons/2020/09/29/expanded-extensio...
Alternatively, you can use Fennec F-Droid, a fork of Firefox that supports a "Custom Add-on collection" by default: https://f-droid.org/en/packages/org.mozilla.fennec_fdroid/
I'm not sure why Mozilla is refusing to allow these extensions on the Beta channel, since the WebExtensions support is definitely stable enough for Firefox Beta.