MacBook Pro admin/standard user issue!!!

Hello guys, hope you doing well.

I have a serious issue with my Mac, i cannot use the admin password to setup anything. I tried everything find in the web to correct this, but anything work.

When i want to open the padlock, there no admin name I enter the user name aaaa, it never work. I reset the password and remake the process, it doesn't work. I updated my Mac to MacOs Monterey, after the process, I cannot find the app that was installed, my desktop is blank, there no folder. I find them I an other volume store in the Mac.

Please, how can you help me ?