I liked the Critical Drinker's take on multiverses in his video where he compared Multiverse of Madness with Everything Everywhere All At Once. It can be used in telling a good story, or it can be a device that ruins the story because it takes away risk and finality (and good luck getting the human brain to comprehend the stakes of destroying a multiverse).

It also reminds me of time travel. I started watching End Game wondering "How will the universe get fixed? Maybe the Celestials will get involved? Maybe a magical mcguffin or a trip to where the infinity gems originated from?" When the movie made it clear that the answer could be time travel, my reaction was "Damn it. I guess I don't need to see the rest of the movie to know what happens next."