Hi, I'm having the issue with my phone where I can't set a lockscreen pin, password, or pattern. This started yesterday when my phone stopped accepting my pin so I couldn't log into it. I factory reset my phone and restored from the Google backup and the pin works there. However, when I try to set a pin now it says "Screen lock was already changed, try again with the other lock screen".
Exact same issue as this previous thread: Solved: Lockscreen + Password Issues - A Discussion about the broken security - Samsung Community
I am also having this issue. In mid-December 2020 my phone decided to not accept my pin. The phone ended up resetting itself and even after a reset, I can not set a pin or screen lock at all. I have tried resetting the phone again, using a different account, and I even waited for the Android 11 update. The phone is now on the latest version and it still won't let me set a lock screen at all. I was getting the "Screen lock was already changed, try again with the other lock screen". error before the android 11 update, but now the app just crashes.