I have a Roku (apart from a static ad on the home screen, I haven’t noticed any problem with them and if it was really an issue I could use adblocking DNS servers), and can play media on it from a NAS drive, or I can plug a USB drive into my router and access it that way. It’s all controllable via the remote and provided there’s good WiFi signal, doesn’t require a fast internet connection. Saying all that, I do have fast internet and usually just stream stuff to it via my phone/tablet and the video caster app.