This appears to be a known problem - on occasions, following a Samsung update, when you are then told to comlete the update restart the phone

1. Restart your phone: Sometimes, a simple restart can resolve minor software glitches. Turn off your phone, wait for a few seconds, and then turn it back on.
2. Check your lock screen settings: Ensure that you haven’t accidentally enabled any additional security measures such as a password requirement for outgoing calls. You can review and modify your lock screen settings in the phone’s settings menu.
3. Update your phone’s software: Keeping your phone’s software up to date can help fix known bugs and security vulnerabilities. Check for any available software updates and install them if necessary.
4. Contact Samsung support: If the issue persists, it may be best to reach out to Samsung’s customer support for further assistance. They can provide specific troubleshooting steps or recommend a solution based on your device’s configuration.

Samsung phone locking itself asking for password or code - Samsung Global issue ! - Samsung Community

It has been mentioned on some sites, that for some reason when a password is set for some app on the phone, it can then cause the phone to ask for a password, if that app has control over aspects of the basic phone operation.

There has also been mention that logging into my samsung - can solve it (I think you aleady have to have that account setup - but I am not sure)
What is Find My Mobile and how can I use it to locate, lock or wipe my device? | Samsung UK

see unlock my device
Find my phone allows you to unlock your phone remotely when you have forgotten your unlock method.

If you use this function, all of the screen lock information (Pattern, Pin, Password and Biometrics) on your phone will be deleted.

 

I own an A12. To answer a call, I have to swipe upward from the green button. To reject a call, I have to swipe up from the red button.

My older Samsung, I swiped left or right to answer or reject a call. I lost a few calls because I was swiping across instead of up. <sigh> I wish they would stop fussing around and changing things from the way they used to be. Answering a call is pretty basic and it annoyed me that I couldn't answer my phone!!!

 

Samsung changed it again. You no longer swipe up to answer or reject a call on the A12. Now you put your finger on the answer icon and swipe right towards the middle of the screen.