This is because of YouTube‘s obsession to build cross-platform, lowest-common-denominator apps, resulting in mediocre experiences across all the platforms they support, and rarely excellent on any single platform.
Their Apple TV app is basically a web view which doesn’t conform to any of AppleTV’s UI principles. Same as their YouTube TV app. It’s sad.
https://www.androidpolice.com/2020/01/30/why-youtube-videos-...