The IronFox version of Firefox works excellently on my 2019 Shield TV.
Also the DuckDuckGo browser blocks a ton of stuff on my 2019 Shield TV when first installed via NeoStore (F-Droid and other repositories frontend) then upgraded via AuroraStore (Google Play Store frontend) or Google Play itself. I've found that I had to use that sequence because it could not install initially from the Play Store, but maybe that has changed.
Another browser option is Cromite, which is a hardened Chromium for Android.
Also the DuckDuckGo browser blocks a ton of stuff on my 2019 Shield TV when first installed via NeoStore (F-Droid and other repositories frontend) then upgraded via AuroraStore (Google Play Store frontend) or Google Play itself. I've found that I had to use that sequence because it could not install initially from the Play Store, but maybe that has changed.
Another browser option is Cromite, which is a hardened Chromium for Android.