It's not that the MCU was "done" but there was a clear buildup towards a giant team up vs an overarching enemy.
Everything after that is just a bunch of vague one-shots that don't have clear direction or any real purpose linking to other films, yet still require you to know a ton of backstory and side characters to "get" it. It's like asking the audience to do homework with no payoff.
Also the wiring quality did drop noticeably, partly because they're running into the problem of trying to incorporate lore from 30 other movies into each one.
I haven't seen it. But to be honest, I haven't watched a Marvel film since Avengers: Age of Ultron. It just feels like they're recycling the same stuff over and over.