Slow to start after a refresh

### Steps to reproduce

1. On develop.element.io, hit Refresh
2. See the "loading" screen for a long time

### Outcome

#### What did you expect?

I expected Element Web to launch reasonably quickly.

#### What happened instead?

It takes 3 minutes or longer before I can see the room list, timeline, composer etc.

I think this got worse in the last few weeks, increasing from about 1 minute to much longer.

### Operating system

Debian 12

### Browser information

Firefox 140.0.4

### URL for webapp

develop.element.io

### Application version

Element version: 814f4a85dfcb-js-c2d25d937739 Crypto version: Rust SDK 0.13.0 (f64839e), Vodozemac 0.9.0

### Homeserver

matrix.org

### Will you send logs?

Yes