Hi there, Pilo7.
It appears that, after upgrading your MacBook Pro to macOS Big Sur, your login password isn't being accepted since the keys that your pressing for a US keyboard layout has changed to a Spanish layout. We can understand how frustrating this would be, and we're very glad to help.
How to use safe mode on your Mac - Apple Support -- Restart your MacBook Pro in safe mode, and see if it changes the keyboard layout. Depending on whether or not it's working as expected, refer to the additional steps below:
"If the issue continues in safe mode
If the issue continues while in safe mode, or your Mac restarts several times and then shuts down while starting up in safe mode, you should reinstall macOS and make sure that your Apple software and third-party apps are up to date.
If the issue doesn't continue in safe mode
If the issue doesn't continue while in safe mode, leave safe mode by restarting your Mac normally. Then test for the issue again. The issue might be resolved.
If the issue returns after leaving safe mode, startup items are probably at fault. Apps can install such items in numerous places, and they aren't always easy to find or recognize. For that reason, you should first make sure that you've installed any available updates for your Apple software and third-party apps.
If updating your software doesn't help, try any of these solutions:
- Test your login items.
- To learn whether software in your user account is causing the issue, set up a new user account, then log in to it and try to reproduce the issue in that account.
- Unplug all accessories from your Mac, including printers, drives, USB hubs, and other nonessential devices. You could have an issue with one or more of those devices or their cables.
- Reinstall macOS.
If you still need help, please contact Apple Support."
Take care.
