can`t really help you but any solution containing the word "persistant" should be avoided.
As long as you follow above you might be helped in the future.
I don't mean to be pedantic, but what you're referring to is the "persist" partition - you are correct, though; messing with this will break your Widevine L1 and it's nearly impossible to get back. This partition also contains all your sensor information (accelerometer, gyroscope, proximity, etc.)
Though it can be restored using OrangeFox recovery, messing with it is still a bad idea and, like you said, will definitely break Widevine L1 with no way of restoring it.