I cannot overstate my disappointment

Rating: 6/10 (27 April 2019)

To clarify, I am not an MCU fangirl. I enjoy these movies a little more than the casual moviegoer but I definitely do not fit into the diehard category. I enjoy watching most of the films, but would only list the GOTG movies and THOR: RAGNAROK as personal favorites.
So just know, this isn't coming from the perspective of some unpleasable geek. It's coming from someone who was emotionally invested in these movies, enjoys most of them, and prizes solid storytelling.
And let me tell you, as a story, ENDGAME is a mess.
Character development? Forget it! Thor's arc from selfish braggart to responsible king is thrown away so he can be Lebowski 2.0, complete with sunglasses and sweater. The Hulk and Peter Quill are pretty much jokes. Tony Stark gets one of the cheapest deaths in modern cinema-- it feels less like a natural culmination of the character's growth and more like RDJ wanted to make sure he wasn't shoehorned into more movies through 2050.
And don't get me started on how the events of this film are going to wreck GOTG 3. Let's just say all Gamora's character development is in the trash now. I know plenty of people who love the GOTG movies but have no interest in any other Marvel property and they'll be confused as hell come 2021. (I really do not get people who claim these MCU films work as self-alone pictures. 9.5 times out of 10, they really don't at all.)
ENDGAME continues the trend of CAPTAIN MARVEL in throwing continuity to the winds. What happened to Thor's hammer NOT being the source of his power? Now, Steve Rogers can use it to toss lighting everywhere like a rogue Pikachu. Peter Parker goes back to high school in 2023 and somehow Ned is still a teen attending--- even though he was one of the confirmed not-deaths after INFINITY WAR. Steve Roger's wild time travel ride at the end will also screw future timeline continuity up in ways I shudder to contemplate. I pity the screenwriters is all I gotta say.
I won't say this movie is the worst. Compared to something like, say, THE LAST JEDI, which had the most formless, meandering plot, ENDGAME moves quickly and does not overstay its welcome. There are some truly fun fight scenes and one-liners. The final battle in particular is marvelous, giving me some of the most fun I've had in a theater in a while (though it could have just been the enthusiasm of the crowd working its magic on me).
But I'm not going to pretend this is an epic finale. It was so unsatisfying a conclusion for the original Avengers team that it kind of taints what came before. What enthusiasm I had for the MCU to come wasn't exactly high (nothing good lasts forever, as many a former successful franchise has shown Hollywood time and time again), but now, my hopes are nil.
EDIT: I found out that Thor's hammer does allow worthy wielders his power, so I rescind my "rogue Pikachu" complaint. The movie is still frustrating though.