There are so many things wrong with this reasoning...
1. There's a high probability your PC is faster than your PS4
2. That's in large part thanks to the thousands of PS players suddenly joining Cubecraft, and Cubecraft not having the infrastructure to deal with it
3. Nintendo Switch?
4. Doing something like this is incredibly hard to do, and borders on impossible
5. That's the worst piece of evidence I've ever heard, because it's biased, and is circumstantial
My pc barely runs 20fps on a good day and I said that the lag with PS players joining and them lagging themselves are intertwined.
Nintendo has often shared games with Xbox and is too small a competitor to really need to bother about.
I dont know the context for the last 2.
If for 4 you are saying its hard to lag a single player its not too hard, make the connection weak enough so they will lag but not crash or make them reload while in the server.
For 5 im guessing thats an overall statement and I did not try add any bias as im not shading the producers of how crossplaying on games has to work or how some bits may be a bit fishy im only trying to point it out.