You should have the same name as a Youtuber on every platform (Xbox, Playstation, Nintnedo and Steam)
But a few minor differences are ok
At least a similar one, if you want to identify yourself. This makes it easier to recognize you
Yes
Unless the name is occupied, you can make WuffiiiYT _Wuffiii_ etc.
If it can be realized, then it would at least be an advantage.
Would it be a good thing if I was called Nintendo, Playstation and Xbox: WuffiYT and different on the PC
Yes, of course, as long as you have a very similar name. But use something secret as a user name on Nintendo, since this is not the name that is displayed and is only for protection when logging in
Yes, I think so, because you don't get confused.