Hmm maybe because there was a writer's strike for five months, and now probably because their new Big Bad is fired because he's a domestic abuser (and too dumb to get out of a relationship with the type of girl that steals your phone and runs away). A lot of the next phase was riding on Jonathan Major's Kang, now they either have to re-cast him, which is definitely doable with Kang, or rewrite the next phase.
Honestly they need to take a break and come back and reset. The MCU has gotten to complicated and interconnected, and people are starting to give up on it.
It's just mostly boring, Ant-Man, iron man and strange are all the same quippy prick and I like all of them but it doesn't really make for engaging media anymore.
They can't pick a tone consistently at all and the interconnectivity is useless if the only impact of one movie is the knowledge of it in the next.
I feel the whole multiverse thing is a bit too nerdy for the mainstream audience. Time travel as well. Also, the novelty of the cinematic universe has worn off.
Marvel burnout from consumers, a lack of anything resembling coherence post-Thanos, too many properties to stream to keep up to date, lower quality and movie reviews, including some complete flops... I'd wager the execs are shitting themselves