How many other finger prints have been enrolled, both in this user account and in any other macOS user account on this laptop?
Do you have an Apple Watch? I just saw another post where a user was unable to enroll a fingerprint (different error message though) and they had to remove/disconnect their Apple Watch (not entirely sure since I don't have an Apple Watch).
Have you tried a simple reboot?
Try booting into Safe Mode to see if that makes any difference.
Try creating a new macOS user account. Log out of the current user account, then log into the new user account to see if you can enroll a fingerprint.
Try a DFU firmware Revive which resets the T2 security chip & system firmware. Make sure to have a good backup first since you could lose access to the data if the process is not able to complete successfully.
Try running the Apple Diagnostics to see if any hardware issues are detected. A passing diagnostic does not mean the hardware is good.
Make sure to always have frequent and regular backups of this computer since the Logic Boards on this specific model tend to have a high rate failure. Plus there are a lot more new ways to permanently lose access to the data on the internal SSD.
