How to get key to decrypt msgstore.db.crypt12 database in Whatsapp in non-root Android?

I want to decrypt msgstore.db.crypt12 in my non-rooted android phone. I tried multiple steps using adb but nothing worked run-as com.whatsapp adb backup com.whatsapp How can I do so? Is there any way to backup full android to a file on laptop and extract key from it? Please suggest.