Fair enough but I think you can make a trilogy work when you structure a main narrative to exist over the course of three movies while having minor plot points that get wrapped up along the way. That for me is good storytelling and a familiar trend of many of the best trilogy movies. Lord of the Rings. Star Wars. Nolan's Batman movies. Etc. They all have individual films in their series that stand out on their own merits instead of feeling just like one big movie split up between 7/8 hours.
See above but you're right in saying it's not just a Marvel thing. Dune did it too and I remember seeing a few posts on here criticising it, which I thought was fair enough.
That's fair, for me it was a minor issue in an excellent movie. Sometimes I get wrapped up in this stuff a bit more if the movie is bad but the quality of it made me not be bothered by it as much as I perhaps would have before.