I got some cheap ONN boxes, Which seem like the best value for true Android TV devices. If you have the funds NVIDIA Shield TV is probably the way to go.

It's possible to skip the Walmart account login at setup, but probably not possible to skip the Google account sign-in (let me know if you find a way!).

Setting up side-loading is trivial, although largely unnecessary. I loaded Stremio, Jellyfin, and a VPN for better streaming experience and control. I replaced the default home screen with Projectivy Launcher. You don't need to go into ADB shell or anything like that. There are also other home screen launchers that fix the major problems with the default GoogleTV screen; Emotin UI (closed source), FLauncher (dormant), Leanback Launcher, ATV Launcher (closed-source).

There are lots of options for web browsing, File Explorer, on-device media, stores, etc. that are easily available.

I would love to exit the Roku ecosystem. I don't use any Apple products and I'm not interested in starting.

It's amazing how there are really no open-source products in this category of devices.