I have an AMD APU Linux PC hooked to my TV with a Logitech K400. Its a bit more fiddly than a throw away android based TV stick thing but you have complete freedom and control.
I watch everything on my web browser with a fancy OLED monitor. The problem is that many services won't give you even HD, let alone UHD. I'm stuck at 480p for renting movies on YouTube.
Android TV sticks scare me, but the Apple TV seems... okay.
Ryzen 5 4600G on an ITX board with 16GB RAM, 512GB NVMe and hard-wired gigabit. It's hooked to a ~40 inch Sony 1080p dumb TV via HDMI.
I don't use fancy GUI media centers or anything, just a standard Debian XFCE desktop scaled up. Netflix and Hulu work just fine in Chrome and Firefox. No idea about 2k+ performance due to 1080p limit. TV for me is mostly background noise so media quality is of no concern to me.
My only gripe is once in a rare while the audio goes to shit and continually crackles but reboot and its fixed.