To be clear, bournemouth76 is the author\owner of the video, I just happened to be one of the first viewers of the video, which at the time was initially uploaded in SD , but bournemouth76 reposted it, or updated it on YT, and then when he did that, it was private for a bit then the next time I viewed it, it was HD, which looked much better..
Now today (and yesterday probably ), it indeed shows up as 4k/2160, now for the few videos i've uploaded that are perhaps a few minutes long like this one, YT near as I can tell, has never taken anywhere near a day to complete all the encoding it does from a 4K source down to the seemingly very silly 144p.. Why ever bother encoding a video of HI-Res origin beyond say 720p or perhaps 480p at the absolute lowest.. But thats what YT appears to do. unless there are settings I have not found that controls how much encoding they might do to one's uploaded video...