Both Element Web and Desktop suffer UI lag and unresponsiveness when loading many redacted messages, and prolong lag by loading older redacted messages without user input

[catscratchedme]

Steps to reproduce

This happens when your client loads a Matrix room with many redacted messages in a row. Element will collapse those messages, and represent them with something like "12 messages deleted."

The Element client will continue loading more and more collapsed groups of older messages redacted messages, I'm assuming because it's trying to load messages until they fill up your screen.

The problem is, the redacted message can collapse into groups of over 100 messages. So the UI lags horribly as Element keeps loading more and more older messages, even though the user is not scrolling up, or otherwise indicating that they want to keep loading the older messages

Possible Solutions:
Maybe if Element detects that there are x many messages redacted and collapsed in a row, Element can prompt the user to click a button indicating that they want to load older ones.

Or maybe make the UI representation for groups of collapsed redacted messages get taller as the number of redacted messages in the collapsed stack increases.

Steps to reproduce:

1. Redact hundreds of messages in a row
2. UI lags and becomes unresponsive while redacting
3. After redaction is complete, UI is STILL laggy and unresponsive while trying to load older redacted messages in the room
4. Lagginess and unresponsiveness persist, even after clearing cache
5. UI lag and lack of responsiveness is only fixed by sending many messages in a row to fill up the screen, and then clearing cache and reloading

What happened?

Element tried to load the hundreds of older redacted messages, and the UI lagged and became unresponsive

What did you expect?

I expected the Element client to just show me that there were recently some redacted messages, and then continue working smoothly and responsively.

Operating system

Linux Mint

Application version

Element version: 1.8.5 Olm version: 3.2.3

How did you install the app?

https://element.io/get-started, and the web app served from homeserver

Homeserver

No response

Have you submitted a rageshake?

No