can you switch from a wekly rom to a stable rom without losing data?
You might be able to.
What I have done is take a TWRP backup of the Data partition just before flashing the new rom.
Then I do a dirty flash of the new rom, wiping only Dalwik and Cache.
Then you have to reboot at least once into system, without flashing anything else!
If it still doesn't work normally after rebooting a few times, boot into TWRP again and restore the backup you did of the Data partion (and nothing else!).
That has worked for me going from MIUI9 to MIUI 10, android 7 to android 8.
If that doesn't work either, then you have to do a clean install like you were "supposed" to do, i.e. wipe the Data partition and then reflash the rom.
So all you risk is the time it takes to do all this, nothing bad should happen.
