The thing is wokeness and bad scripts aside, the multiverse just isn’t really that interesting a concept as the infinity stones were. The thing with the stones is that it is simple concept to understand. They are individually powerful and together allow you do potentially anything, therefore a bad guy trying to get them all is bad…simple. The motivation for someone trying to get them is easy to understand, and it’s easy to understand why it needs to be stopped.
The multiverse isn’t like that, there’s nothing inherently bad about it. It’s just there. You need to create stories that focus on a bad guy trying to somehow exploit it, but he’s a bad guy trying to do evil thing and how the multiverse relates is just a mess.
The other thing was that older movies had a self contained story that had an element that connected it to the rest of the MCU, mostly one infinity stone. The multiverse is central to this phase, the movies aren’t really self contained with something connecting them to the rest of the MCU. The multiverse is central to each movies and more often than not it’s just a bigger concept than some of the heroes are designed for. Ant-Man is at its best with a small relateable story about family and trying to do right by them. Not intergalactic, space, multiverse type of stories.
Just my take, I think even without being woke this phase was doomed to fail for relying way too much on a concept that’s hard to grasp, and had way too much interaction between each movie and tv shows.