rtx3090, 5800x3d, wayland, sddm, kde:

• whole system freezes on boot (with somewhat garbled display) when display manager starts (sddm) - IF >1 displays are plugged in/powered on.
• no issues if sddm starts with one display, and THEN powering up second. - But this has to be done while in sddm, before logging in.
• whole system can (with high chance) freeze again on desktop if at any point a screens are connected/disconnected
• krunner works exactly once, after that it logs errors in journal that some display reference is wrong (the exact wording escapes me atm)

all these things were fine with 570.86.something - the previous version, which apparently was beta.