I tried to use adaway but I can't do root and I already use a VPN. 😭 Thankfully I use NewPipe x Sponsorblock and ublock origin in Firefox so I'm usually covered.
Sometimes things open in-app and use Google to load the page, so even if I select "open in firefox" after, there's still an ad. Plus ads in apps in general.
You can get the FFUpdater app from F-Droid, then use that to install Brave to your phone. But at that point, you may as well just use FFUpdater to install the much better alternative, Firefox, which doesn't indirectly support Chromium engine dominance and doesn't have that weird crypto crap Brave has.
Edit: Someone else replied to you suggesting Mull, which is also downloadable through the FFUpdater app.
What I thought was that Mobile had it's own built-in adblocking. I specifically remember being able to add the extension in a way I wasn't able to a few months ago recently.
yes: Firefox Mobile supported extensions for years, but only mobile-specific extensions, which was limited to Darkreader, uBlock, Decentraleyes and a couple more.
the new change is that Firefox Mobile will support all desktop extensions, though I'm not sure if it's implemented just yet