why my MAC PRO keep asking about the "login" keychain !

If your Mac keeps asking for the login keychain password

The password of your macOS user account might not match the password of your login keychain. Either create a new login keychain or update it with your new password.

https://support.apple.com/en-us/HT201609#:~:text=Either%20create%20a%20new%20login,password%20of%20your%20login%20keychain.

Even if you THINK you never use keychain, your network password and your email password(s) and your Apple-ID password are stored in it automatically. So it is important to get it working again.