I upgraded without wiping data, and everything seems to work 
- reboot to TWRP
- flash LOS-18.1 zip
- flash opengapps-pico-11-test zip
- clear Dalvik/ Cache
- reboot to system
Trust complained that image is signed with public keys, but that’s all (I could dismiss this message in Trust options)
Thants to every contributor <3
EDIT: seems that Magisk didn’t survive the upgrade, but Manager is still installed so I can reinstall 21.4 from there 
EDIT2: not possible from the Manager, so I flashed it with TWRP:
- flash Magisk 21.4 zip