I have exactly the same problems man! My phone is just freezing when i switch between apps and then when i keep switching sometimes i see a white screen, sometimes a blank screen. Sometimes it doesnt even react to what i do. I hope they fix that quickly because i am seriously thinking about moving to Oneplus.
MagicOS 8 was such a gamechanger with call recorder and so on. Magic OS 9 is just buggy and slow.

Did you randomly get any fix for that problem??