All Electron apps are slower by orders of magnitude than the native ones by definition. Trying any non-Element client might help.

Could you please suggest one native android client?

A sibling comment [1] says it works fine on Mac and Windows, and it's all the same desktop app. It's likely a Linux quirk that hasn't gotten enough attention yet

[1]: https://news.ycombinator.com/item?id=32021303

There are plenty of apps that run smooth on Linux. If there is a bug, then it almost definitely isn't due to Linux itself. Maybe they could just admit their development efforts aren't actually focused on optimizing for open source.