And exactly what? Sorry, your post makes no sense. It's like a fragment pulled from a conversation with your mom and does not contain any useful info nor is it actualyl a proper question.
Agreed. Not too sure how to reply to your question. For all I know youtubes video quality can only be determined by them, and maybe other small factors to why it wont show clearly on your screen. Such as having too many open tabs, downloading or streaming other media while using youtube (I do this sometimes and causes bad vid quality performance), and also using HD 1080P can degrade performance as well.
Maybe you should also consider contacting Youtube to get better detail to your questions needs.
I haven't seen specifications from Youtube yet. Here is what they currently have published: Recommended upload encoding settings (Advanced) - YouTube Help
I would not count on more than about .005% of your potential audience being able to stream 8K videos any time soon. I wouldn't even count on a monitor that can take advantage of 8K video any time soon unless you have a very big wallet. 8k tv