I got a little nervous about the mixed/poor reviews the last couple of days but having seen it, I have to say they're almost entirely off base.
Is it the greatest thing Marvel's ever done? No. But it's pretty high up there. A massive improvement over Dr. Strange - which I didn't even particularly dislike though it is kind of the definition of middle of the pack Marvel - and, imo, at least a bit better than No Way Home, which was certainly very good, too. There are maybe five or six that I would say are definitively better than this one. No more than that.
The film looks gorgeous. The action is great. It's easily the most magical movie in the MCU and really (finally) delivers on the promises people made about the first DS film being so visually mind-bending. The central character arc for Dr. Strange is one of the best in the MCU and incredibly well done. America Chavez is a great addition to the franchise, fun all the way through the film and while I've seen some people argue she's too shallow/cliched, it's not exactly like the original introduction of Falcon or War Machine or, well, almost any secondary character in the mcu was any deeper than this. She is still a secondary character in this movie.
Wanda is the part of the film that's going to cause the most controversy for obvious reasons. I'm not necessarily wild on the direction her character is sent in because of this film, but I do think it makes sense enough as a followup to WandaVision (and in the context of the specific rules of MCU magic wrt the effect a certain item has on people in general). I also have to say Elizabeth Olsen absolutely killed it. So while I wonder about the future of the character and may be significantly less thrilled about this movie in the future if the character's future really doesn't turn out satisfactorily, right now I think this is a damn good story even I would've preferred a different one.
As for all the 'not multiverse enough' reviews, that's horseshit that tells you more about people's ridiculously unrealistic expectations than about the film. Its as 'multiversal' or moreso than Into the Spider-verse. The only thing it really isn't is a giant cameo engine for all the famous actors from previous movies and shows or an endless whirlwind through dozens of alternate universes. Which is obviously a good thing, because it still has an actual story to tell that involves specific characters and specific places that are important. The multiverse stuff is very specifically there to serve those characters and that story, not the other way around.
I don't think you are missing anything amazing here if you do that. I got my moneys worth but I did notice people shifting in their seats.
I do that at literally every movie. Theater seats just aren't that comfortable.