OK, i got the latest 20.4 magisk working now. Basically after ROM installation i updated Magisk in TWRP -> 19.0.zip -> reboot -> 20.4.zip. No bootloops.
On my OPO, 5GHz Wi-Fi causes pretty frequent wakelocks, regardless of rom or modem/firmware. Took me a while to figure it out. Foxed by moving to regular 2.4GHz