When I saw that my bank application was not working I tried to remove the permission to unlock the bootloader, which was not greyed out in the developer settings. This did not solve the problem, but to reactivate the permission to unlock the bootloader I was asked for the special code again and I was afraid that I would have to erase all my data again, so I left it like that. Later I noticed the option had become greyed out.
First I updated the Magisk app when I saw update notification. Then I directly install Magisk and reboot as usual. After that I saw that the Magisk application had disappeared and that each time I tried to reinstall it, it disappeared again when I wanted to run it. Then I gradually discovered the other malfunctions: wifi, heating, sound.
Yes. First I tried to reinstall Magisk according to your other post, but it failed and things started to get seriously messed up. So I decided to flash the original FP4 rom, but got “Critical partition flashing is not allowed” message in Fastboot.
“unlocked: no”
All this looks like to this other post Finally the FP4 ROM file is available - #14 by EmmanuelH
Thanks again for your help !