I can’t remember my Mac account user name
I don’t know how to login without my username
MacBook Air 13″, macOS 12.4
If you don't have a different user account you can boot into, see if you can add an admin account using the steps in the article below. Then boot into the new account, go to System Preferences/Users & Groups, and you will be able to see your user name. You can then reboot the computer and sign into your normal user account.