IF - and that's a big IF - this multi-verse angle turns out to be true, I think that might be a bridge too far for me. Time travel is one thing, but once we open up this cinematic universe into infinite universes, it all starts to lose a little weight and consequence for me. It's just too much. That, and especially on the heels of Into the Spider-Verse, we're potentially doing kind of the same thing here as well??? Is that now a Spider-Man franchise prerequisite? With Into the Spider-Verse, that was the whole conceit, and it worked phenomenally well, obviously, but to introduce that into the MCU... no thanks.
That said, yeah, SURELY this is a ruse put on by Mysterio, as that's his whole thing.