I'm currently using TVBro but I'm not very happy with it. The adblocker leaves a lot to desire, streaming crashes quite often, audio gets muffled, etc.
I tried sideloading some Android browsers (e.g., Brave, Firefox, Chrome) but they don't support input through the TV remote and I can't really interact with the UI without mouse/keyboard.
Firefox for Android TV doesn't have adblocking/extensions.
I found native Android TV browsers like Puffin to be rather trash, or don't really block ads.
What other options are out there?
Try BrowserHere https://play.google.com/store/apps/details?id=com.tcl.browser