What’s your budget? The Walmart ones might be all you need. Do you really need it to be Android TV? I have both Roku and Google TV clients. I like the Roku one, but not a fan of the closed ecosystem (can’t side load or adb).
You shouldn’t need anything crazy to play your media, but if you go with Google/Android please replace the default launcher. You will very happy then lol.
The Walmart “onn.” has been perfect in my household. Dirt cheap at $20, degooglable, good remote (you can use an app to rebind the streaming service buttons to apps you actually use). Supports the Google cast protocol and also SmartTubeNext. No ads of any kind on the home screen, because I’m using a custom FOSS launcher.