If you had a machine that created a window through which you could see the future, and in the future you wrote down the winning lottery numbers and relayed that information to your present self before that lottery number was drawn.
However, in your present selfs excitement, you turn off the machine before your future self wrote the winning lottery numbers into it for your past self.
What would happen?
Invincible can’t move between the infinite timelines though, and no storyline is hanging off of the important changes he makes those timelines by travelling through time/dimensions. He’s not “saving” anyone by jumping through to another universe
Yes, that’s the restraint the writers are showing. That’s my point: the issue isn’t the multiverse aspect itself, it’s the replacability brought on by unrestrained multiverse implementations.