Is there a Waterfox for Android?
I understand but just like one said "cybersec is just a panic control". I don't know if you are really really vulnerable especially when non-harden updated Firefox is more vulnerable and less secure than hardened a little outdated forks. If that's not a crticial CVE I don't see an issue on my GrapheneOS. Google could convince you not to use Firefox and use Chromium instead because they can control security for you not Mozilla so it also depends on perspective.