Best Practices

We recently acquired a new client who uses a 2022 SQL Server database. The database is set up with mixed mode authentication. Unfortunately, the Windows account in use lacks sysadmin rights, and the client doesn't know the sa password.

I've attempted several methods found in online tutorials to reset the password, but none have been successful. For instance, we tried restarting SQL Server in single-user mode, creating a new user, and assigning the sysadmin role to it. While the commands seemed to execute correctly and the user was created, it didn't receive the sysadmin role (see commands below).

We also experimented with a commercial product designed to reset SQL Server passwords. This, too, appeared to work but ultimately failed.

Is there a definitive method to reset the sa password or to create a new user with sysadmin privileges? Any assistance would be greatly appreciated.