So what’s the best android tv box nowadays? Still the Shield TV?

I have the latest chromecast with android tv (i think, who knows with these garbage model names), and it’s always been quite sluggish to use, and I can’t replace the home screen on it to one without ads since they locked down the bootloader.

So I’m looking for one that’s a bit snappier, and preferably with an unlockable bootloader, or at least the ability to replace the default launcher.