now i'm stuck thinking about what a good (or at least better) ending it would have been if, after thanos gets dusted, and because they just killed thanos before he ever did the snap in the first place, and because we've now been told there can only be one "sacred timeline" i.e. there can't be one timeline where the snap happened in 2018 and another where thanos vanished in 2014, reality just..... changes so that the snap never happened at all
tony snaps his fingers. the screen goes white. he's sitting in his basement lab at the cabin, unhurt, and rushes upstairs to find pepper and morgan at the kitchen table. pepper remembers nothing about the snap. someone knocks on the door, and it's peter parker -- visibly 5 years older -- bringing donuts, ruffling morgans hair, "hey mr. stark! i brought boston cream"
steve is at home. he immediately calls bucky, then sam. neither of them remember the snap either. he calls natasha, and holy shit she picks up, she remembers everything up until her death on vormir, but she's alive. like it never happened. team cap gets together and they tell sam and bucky everything. they realize that killing younger thanos must have changed the past. they call bruce to ask hey wtf happened, i thought you said that wasn't a thing, but his phone's out of service for some reason?
bruce is in space. on the statesman. apparently it takes more than five years for a ship that big to make it across several galaxies, because he asks the first asgardian he sees "hey how long have we been in space" and they laugh and smack him on the back hard enough to bruise and say "you midgardians with your jokes, you know it's been five earth years" and he's like holy shit holy shit holy shit and goes searching for thor. he finds him in a hallway already hugging the stuffing out of heimdall, who is taking it in stride, and through blubbering tears thor's like "bruce! what happened to changing the past doesn't change the future!" and bruce a little manic is like "IT WAS JUST A THEORY MAN it's not like i had a lot of experience with time travel!" and thor hugs him too, and while the three of them are loudly discussing this in the hallway (and heimdall reassures them that, yes, natasha's alive, and yes, all the other original avengers are going through the same confusion these two are) a nearby door glows green and slams open and loki's like EXCUSE ME but SOME OF US are trying to SLEEP so if you WOULDN'T MIND-- and thor tackles him in a hug, crying again, and loki's like. i don't. i don't know what's happening. he looks over thor's shoulder at heimdall and bruce, who just shrug, and loki deflates and gives in and hugs his dumb crying brother even though he has no fucking clue what he's crying about. bonus points for "i'm right here, you idiot. didn't i say i wasn't leaving again?"
scott lang's at home, in the living room with cassie, and there's pictures on the mantle of the two of them together over the last five years, scott at her middle school graduation, scott and hope with her on a trip to a theme park when she was 14, and cassie's like? dad? are you okay? and he's like yeah :') yeah i'm great peanut :')
we start to hear upbeat 80's music. cut to the benatar, where rocket's suddenly surrounded by noise and the guardians bumping around each other in a familiar chaotic mess. none of them remember anything, except for nebula (and yeah we're gonna have to nix the younger nebula getting killed because that makes me too sad) and... wait, gamora's not here. shit, did resetting the timeline not bring gamora back? and he and nebula realize gamora was taken out of the timeline in 2014. she's never met the guardians, not yet, but she's out there somewhere, probably on earth, probably very confused since she was the only part of the opposing army that wasn't dusted before the timeline reset. and rocket's like "hey quill new mission we gotta go find nebula's sister" and peter's like "another nebula? yeah that sounds uh. terrifying" and they're like... yeah don't worry about it, you'll like her
AND queue guardians 3 a.k.a. the gang reunites with gamora (except rocket's the only one she doesn't know who already knows her), the falcon and the winter soldier except Steve's There In Retirement This Time, wandavision a.k.a. wanda and vision go on a nice non-trauma-fueled vacation, and thor 4: more thor where loki and heimdall and the rest of the asgardians who made it after ragnarok are still alive. the end :)