My Face ID has been disabled on my iPhone. How can I fix this problem??

If you read the Related Article Link at the top of this page, which brought you here and you tried the suggestions and nothing worked, the final suggestion is as follows (from the link):

1. If you still can't enroll your face or unlock your device with Face ID, you can take your device to an Apple Store or Apple Authorized Service Provider, or contact Apple Support about your iPhone or your iPad.

Go back to the article you came here from and proceed to the last step, contacting Apple Support.