I loved it. It was a perfect sendoff for the true MCU fans, and showed so much respect for the comic fans. You can tell that some of y'all missed some of the callbacks to the other MCU stories, or just weren't paying attention. Even the time travel stuff had things that were explained in the movies. The funny thing is that most people figured the plot would be them using time travel to get the stones, but I loved the surprises of the movie focusing solely on them. I think it did help that I ran through the movies, leading up to Endgame.
I loved little the clues they gave along the way.
Cap getting the life that Tony talked about (AoU). All Cap wanted to be was a soldier, Tony wanted them to win so that they get to go home and live a good life. Also in AoU, Cap's vision was dancing with Peggy. We learned in Winter Soldier that she married, someone directly tied into Cap, but they left it ambiguous enough that it could be Cap. They never gave his name. In the end, he goes back and lives that life...2 Caps in the timeline.
Tony started it, and finishes it. He got the life he always wanted, but at the same time, "I am Iron Man" so though he ran from it, he knew what he had to do, and did it. He also got to make peace with his dad before going. Also, the Avengers started with Cap, Iron Man & Thor, and ends with the final battle starting with them.
Hulk & Banner coming to peace, with Professor Hulk. I think Doc Green should've been the persona, so that he could've been used more, but this movie was Banner/Hulk being at peace. Widow & Hawkeye's friendship, as established in the first Avengers. And Thor's epic falloff. I loved Thor's scene with Frigga. Hell, this movie brought as many people back as possible, including Jarvis OG from Agent Carter. I would've loved to see the Marvel Netflix, but that would've been a breach of contract.
For the comic fans, we got Cap being worthy, Rescue & A-Force (y'all really mad?), Stormbreaker + Mjolnir, Asgardians of the Galaxy.
The only possible plot holes I see are with Gamora & Nebula...not so much with Nebula (being that they are on essentially one being, as shown in the movie), and Loki. Salute to Nebula's storyarc. She was an underrated character in this movie, especially how she portrayed past & present selfs. Of course, Gamora could always be sent back to her timelines. As for Loki, in order for it to work, he would've had to have returned so that he could be taken to Asgard and the events play out, BUT they really have a way out since Loki has died/disappeared so many times, that you can't really tell which is which. As for Thanos, we don't know if thy snapped him dead, but I'm thinking they probably snapped him back fro which he came. In short, they lost to Thanos, and have to live with it.