Brave is one of the only browsers on android that does decent ad blocking, but it's chrome based so it also works reasonably well on mobile sites expecting chrome.
It's worth knowing there are also a number of Firefox based browsers that have full extension support, and even the base Firefox app supports a couple extensions including ublock origin, so Firefox based browsers will also do extremely well with ad blocking :)
but agreed, websites definitely don't test Firefox as much as they should though, so you do sometimes need to switch to something chromium based if you want a browser with Mozilla's web engine instead of Google's
Understandable! I know Firefox nightly and fennec, the f-droid compiled version of Firefox both have the ability to use any Firefox extensions, though setting it up is a little more work than one might need to expect. You have to first create an extension group or category on desktop (I dont remember exactly what Firefox calls it) and then you can load that group of extensions as a custom supported list of extensions on your mobile devices. Its not very technical, just requires setting up the group on your desktop first.
There may be other forks that have full extension support, and I'm kinda thinking there are, but those are the two I'm thinking of off the top of my head. But if you look up the forks of Firefox for android/mobile, I'd guess that most or all of them probably have extension support in the same way.
Otherwise, the official app has a short list of extensions that mozilla has tested that you can enable or disable, including ublock origin :)
Hope this helps!
Edit: the extension groups are referred to as " collections" so thats the option you'd be looking for on desktop. Here's a handy link on setting it up from Mozilla :) it should be the same no matter which version/fork of firefox you're looking to enable custom extensions on!
Unfortunately Brave's own blocking engine isn't capable to block as much as uBlock Origin, which Firefox supports on Android. But then Firefox might not work well on all sites... it's a trade-off. Firefox works on the sites I use though, so that's what I've been using.