Improve Space creation time/flow

### Your use case

#### What would you like to do?
I want to be able to quickly and smoothly create spaces

#### Why would you like to do it?
So it's more attractive feature

#### How would you like to achieve it?
Performance improvements

### Have you considered any alternatives?

_No response_

### Additional context

When creating a public space, there is a "Creating Space…" spinner at one point. When the spinner is done, the view goes back to the list of rooms for a second before changing to the new General room. The room creation confetti in the background falls slowly and freezes a couple of times.

On Android 11 on a Pixel2 with Element 1.3.14