One could hope it’s due to COVID, but other production companies have managed to shake off that pandemic rust quite well.
I think it’s more due to crunch time, and not using their resources and budget all that properly.
It’s not just that. When you have movies in production simultaneously. You have to make sure they are connected to the overall universe without having plot holes and not having continuity issues. With leads do rewrites and stuff being left out in the final cut.
This was never an issue in the first 3 phases. Now it is, especially when you add in the TV shows.
The question will always be “why didn’t so and so show up for this event”.
In order to fix this, movies will have to be written well in advance. I think that’s something they have slacked off on. It’s like these movies are connected, but when they start the writing and putting them together, they don’t take head to that until it’s right in the middle of everything, then they end up doing things on the fly. America Chavez was supposed to be in Far From home for example. But because she was already going to be introduced in Dr Strange, they ended up rewriting the entire movie.
And this was because they parted ways with the original director for Dr. Strange who had a completely different plot, and they ended up writing a completely different story.