IceCat is extremely out of date and not secure.
Please don’t recommend it.
If you want Firefox on Android use Fennec F-Droid or Mull, both are available via F-Droid.
You can also see my browser comparison here: https://divestos.org/index.php?page=browsers
Disclaimer: Mull is my project and I also help maintain Fennec F-Droid. I also have a handful of commits in most WebView browsers. bias blah blah
Also fun fact: /e/ Browser based on Chromium 96 is currently vulnerable to 113 known security issues.