I have the same experience...! I run a full Titanium Backup to cloud for important apps and settings every night, so the hassle to get back up and running isn't THAT big. But still. I have had my phone reset this way 3 times since christmas.
You can't really "reinstall stock", there is no stock image available, only incremental updates.
This needs to be explicitly done by an OnePlus servicepoint. But normally they never wipe a second time and then re-flash. But that is the only way to go
It seems I managed to make it stable at last. I've been running the system and rebooting it regularly without problems for the last two months.
It seems that flashing magisk from TWRP was causing the boot loop problems. Patching the boot image manually with magisk app and flashing it later in fastboot seems to work flawlessly, at least for the moment
Installing TWRP is safe, but some features don't work well in this device. For example, restoring a nandroid backup in a device with the boot loop problem will not solve it, so they cannot be trusted. Also, formating data will not wipe everything, it seems to leave traces. Doing the same from stock recovery works fine
You can just flash the magisk zip file in TWRP without any problems on your custom rom?I can't tell on OOS because I've stopped using it since june but there is no problem with root on custom ROM. I'm using Pixel Experience by Sakil Mondal (https://forum.xda-developers.com/t/...rience-aosp-oneplus-nord-2-5g-denniz.4392521/) and it's working great. I haven't tried A13 yet.