after update MacBook does not recognise administrator password

Do you have another admin user?

If you open Users & Groups System Preferences and select your user, is the checkbox set to allow you to administrate the computer?

If no to both, you can try to restart the setup assistant to create a new admin user. From that user, you can give your original user Admin capability, again.

Restarting Setup Assistant to create Admi… - Apple Community

I'm working with another person who can't get to the Data volume in Recovery. When you go to Mount the Data volume, check the name of the volume and use that in the path if it is different from "Macintosh HD - Data."

Since the Big Sur upgrade however, I am listed as "Standard".

There have been a few reports of that here for Monterey--I can't remember if it happened on Big Sur.

If you don't have another Admin user, you will need to create one, then use it to give your current user admin privileges.

Restarting Setup Assistant to create Admi… - Apple Community

There is a setting in Security & Privacy System Preferences to require admin authorization for most of the System Preferences. It is under the Advanced… button.

But, even without that enabled, I have always had to authenticate the Date and Time changes. I don't think that is new in Big Sur, but I don't have much need to alter the settings, so I can't remember. Date & Time are quite important for establishing secure connections, so I don't know it wouldn't be locked down.

I can't make any changes to my settings. It won't let me unlock without the Admin password and it was never like that before...

You won't be able to unless you authenticate as an admin user. I don't know how you went through seven OS upgrades without using your admin account and password. Earlier OS versions may have allowed some changes without the admin approval, but the three most recent have never been a free-for-all. User-centric changes (everything in top section) in System Prefs can normally be done without the admin approval, but changes that affect the entire system require admin authentication. An OS Upgrade certainly couldn't be accomplished without admin authentication.