Of course, this can only happen based on two things:
1) United (and the rest of the big 6 clubs) negotiate with the PL to also play there, along with staying in the Carabao Cup and FA Cup. The European Super League becoming the main league for us (and everyone else signing up) would be stupid to say the least. We are an English club, Barcelona are a Spanish club, Juve Italian etc etc.
2) There is a yearly qualification for the European Super League, thus sides like Leicester, Everton and West Ham can still make it. Otherwise, the top end of the PL, aside from winning it, would be absolutely pointless.
If this criteria is met, then it’s fine. I’ll be indifferent to it. It’s basically just us playing the likes of Real and Barcelona in both halves of the season instead of just the second.