Unfortunately my PC is unable to play any 4096p videos without lag. I can however play most 3840p and even 4000p videos as long as they are compressed h265 versions.
Sadly, videos can only be downloaded in their maximum resolution, which is 4096p for a lot of studios these days, or in 4K (1920p) which is obviously a massive downgrade. So a lot of recent 8K videos are sadly streaming-only for me at the moment.
When streaming videos, there are many in-between resolutions available. So if the videos have already been encoded at these resolutions, why not make them available for download?? It would make a massive difference for me, so please consider it.