TL;DR
It's Apple's issue, use more advanced player or use video converter. Almost all higher-resolution videos (1440p, 4K, 8K) on YouTube today are encoded with VP9 codecs, be it MP4 or WebM. And this codec is not supported by Apple.
AV1 codec
YouTube encodes streams at resolutions above 1080p using the AV1 codec, which Apple does not yet support. Here's an interesting thread about this https://forums.macrumors.com/. It started in 2020, and there's still no report of support being added. The main problem is that this codec is not supported by the hardware, even on the newer Apple Silicon processors, and they don't want the decoding to be software and waste a lot of power and lead to low battery life.
So if you just want to play this video, you better install a more advanced player like VLC, which plays all known formats. But if you want to use this video in your projects, you will have to convert it, and this will take some time (sometimes a lot of time if your computer is not very powerful).
Almost all downloaders on the market download YouTube videos as they are, without conversion, so you will end up with the same unsupported AV1 video file even if you install our competitors.
VP9 codec
Same situation.