[K20] MIUI 12.1.2 Stable to latest weekly, because of bugs?

[Fisatec]

Hallo everybody,
I flashed my Mi K20 with 12.1.2 stable and I am facing some problems now.
The main problems are:
- Push notifications are not reliable, e.g. WhatsApp messages sometimes not show up
- Dual Apps can not access internal storage

Will these Problems be solved with latest weekly?
Is it possible to flash dirty without data loss? I have read several different Opinions and actually don't know how to evaluate.

Thank you very much
Fisatec