I’ve been using it on my phone for a fair bit. I still run into issues from time to time where pages don’t render properly, but that could also have to do with the adblocking which is a major advantage of Firefox. I only use Chrome now if Firefox doesn’t work.
I used to use Brave for years, and tried Kiwi for a fair bit too, but both of them have their own issues. I’ve found that Firefox works well enough for me now and allows me to stick it to the man.
When the day comes that Brein starts sending notices to pirates, these pirates will just move to Newsgroups and VPNs.