I can't really imagine what you believe is so bad about the Apple TV UX. It's a basic grid of available apps and videos, with an easy swipe to access video settings (subtitles, language, etc). Not complicated at all.
Most streaming boxes have the same basic interface... my usual issue is when one is laggy (e.g. TV built-in, Roku, Chromecast, etc). The Apple TV is buttery smooth, fast to scrub through videos, and never feels limited by its CPU.
It suffers from the same issue as all Apple devices, a lack of discoverability. It is even worse on the Apple TV given the lack of buttons on the remote.
I much prefer my Roku TVs and don't have any issue with lag which bothers me.
Yesterday's news. ATV4K remote couple years now has all the buttons and no track pad (well, you can swipe in middle of the round OK button, but you wouldn't).
I like Apple TV. The one thing that consistently frustrates me is pressing the mic button at the wrong "screen" will take you out of your current app and bring you to the Apple TV+ search container. Yes, it's not hard to navigate back to where you were but it's quite simple to accidentally press the mic button at the wrong screen.
Most streaming boxes have the same basic interface... my usual issue is when one is laggy (e.g. TV built-in, Roku, Chromecast, etc). The Apple TV is buttery smooth, fast to scrub through videos, and never feels limited by its CPU.