App Layout: filtering and performance issues

### Steps to reproduce

1. use the new room list

### Outcome

#### What did you expect?
- room list filters instantly as I switch spaces or filter tabs
- room list is coherent
- room list is complete
- room list is shows the correct rooms as filtered
#### What happened instead?
- filtering (for both spaces and the different tabs) is slow to be applied in general for me
- it's also slow to keep the same filter applied when ever i go back to the room list. seems more like it's doing a sync, shows all rooms, then filters them.
- sometimes it's entirely confused and shows rooms from the wrong space but will catch itself after a second or 2
- sometimes it catches itself, fails again, catches itself, etc without end. keeps switching between 2 filters every second or so.
- sometimes rooms from subspaces are missing

### Your phone model

Moto G5S+

### Operating system version

AOSP 10 based

### Application version and app store

SchildiChat 1.5.1 (F-Droid)

### Homeserver

synapse 1.68.0

### Will you send logs?

No

### Are you willing to provide a PR?

No