I thought that it didn't play certain resolution YouTube, as even the newer generations only just got 4k support for due to codec issues?
No, YouTube does not work at all on the second generation Apple TV since 2015.
While (I think) it has rudimentary YouTube support, it does not have an AppStore, or any sort of “ecosystem” around it that would need as much maintenance as an Android device or the APLE TVs running fully fledged tvOS these days, so I don’t think it’s an entirely fair comparison.
In the UK it doesn’t have iPlayer, which is probably the most popular VoD app after YouTube.