Currently you have encryption enabled. You can check in security & location > encryption. Camera, torch And volte are not working due to encryption. To decrypt, You have to format device using twrp[wolf twrp preferred] (go to wipe> then you will find format device there. If it's not there then click advance option and select delvik, data, system, data, cache). Then reinstall rom.
Now You can install magisk 16.0. But this is treble enabled so You must install wolf twrp and enable treble mode in settings.
Wolf recovery and magisk download link are in 3rd post of this thread.