I think we picked the exact right movies for our re-watch this time (before Infinity War we watched all of them, just didn't have the time this time). We watched Ironman, Avengers, Winter Soldier, Ultron, Civil War, Thor Ragnarok and IW which we finished less than an hour before we left for Endgame. So it totally seemed like such a natural continuation for me. Pieces of the movie (including who died at the end) were in line with our theories so in that way, it was kind of predictable but in a good way for me. I loved that they focused on the original Avengers - I mean, yeah they had to since that was who was alive but that's also, for the most part, who's story is ending.
Interesting point about the others being disjointed movies - but at the same time, so was Ironman and Captain America and the two Guardians for that matter. But they still made for really entertaining movies. I think there is definitely opportunity to link it all up if they want to though to bring that integration back. I feel like the characters are so good (and the actors portraying them are perfect) that they will be easy to watch. Though it is definitely not quite the same - kind of in the same way the Fantastic Beasts movies are really enjoyable but it isn't the same as Harry Potter.
I'm not a comic book person so I don't know what's canon/happened in the comics but I really have gotten to know and fallen in love (ie nerded out haha) with the MCU through these movies.