I've been using the Apple Music app on my LG TV since they enabled it for Spatial. Works well, although the navigation is a bit clunkier, and there's no voice search, which is the biggest deficit for me. Still, if my Apple TV unit dies, I probably won't rush to replace it, since I can use the TV app.
My 2021 Apple TV 4K is pretty flaky, actually -- it glitches a lot, and reboots itself out of the blue sometimes. I have to restart it regularly to fix it after it gets buggy. Anyone else have similar issues, or do I have a lemon? I bought it for a reduced price as an Amazon Warehouse deal, which might explain it.