If you're just a regular person not a CBG, Marvel has been
1) Trying to repeat Guardians of the Galaxy success with other d list characters.
2) Trying to get people to subscribe to Disney Plus with (now) A list characters in paint by numbers TV shows
3) Messing up their movies by forcing casuals to watch the TV Shows to understand the movies.
4) Replacing the Avengers with much cheaper and younger actors and directors.
5) Fixing boring movies with boring CGI fights at the end.
That said, they had a good number of bad movies prior to End Game.
The second two Iron Man movies, both Ant Man, both Thor, The Hulk movie doesn't count apparently.
Real talk, Captain Marvel made a billion based on tie in and first female movie but Brie Larson is no Gal Gadot and Sam Jackson singing is the best part of that movie.
And Black Panther 2 made 800M. We would have supported Michael B Jordan as the new Black Panther. He would have probably been the best choice even if narratively difficult. Shuri, both the character and the actor was just never gonna work.
Keeping these bad movies in mind, it was inevitable that bad movies would reappear again. It's just been accompanied by mediocre TV shows, which makes it worse.
For them to fix it, they probably need to chill. Same with Star Wars and Pixar. Like nothing for a few years. Zero. No series, no movies. Scrap all the plans. Better to give everyone a check and not spend the advertising budget.