Lengthy messages causes performance issues

### Steps to reproduce

1- Send a lengthy message of around 5000 words
2- When I open the chat room, it takes longer to scroll through the timeline.
3- And it crashes.

### Outcome

#### What did you expect?
we expect no delay when scrolling through the timeline.

#### What happened instead?
there is a huge delay while scrolling and the app crashes

### Your phone model

iPhone 11

### Operating system version

IOS 16

### Application version

The latest version

### Homeserver

_No response_

### Will you send logs?

No

No source files, tests, or entry points are identified. Reproduce on an iPhone 11 running iOS 16 by opening a room containing a roughly 5,000-word message, then profile timeline scrolling and capture the crash; done means scrolling has no noticeable delay and the app does not crash.

Written by the indexing model from the issue text.