Android support is a bit of an issue and unfortunately that's not something I can fix. A couple of months ago Firefox removed support for most extensions, leaving only a handful that they approve. Tor Browser seems to be going the same route. Chrome on Android never supported extensions.

Aternatives: Kiwi Browser (Chromium-based) supports extensions and perhaps you can install older versions of Firefox or Tor Browser via F-Droid but that might become a security issue in the long run.