MacBook Air wouldn't accept password after I restarted it

The repeating letters could be a sign of a sticky or malfunctioning key. Try cleaning the keyboard carefully, especially around the keys that are repeating.

Since your account is locked for a period, wait until the lock period expires before attempting to log in again. Make sure you're entering the correct password. Sometimes, keyboard issues (like the repeating letters) can cause incorrect password entries.

You can try to do this to reset your password

If you forgot your Mac login password - Apple Support

+ If the password still isn’t accepted, you might need to reset it.

If keyboard issues persist, consider connecting an external keyboard to determine if the problem is with the hardware of your MacBook's built-in keyboard.