Hi smokymoon,
Thanks for reaching out in Apple Support Communities. I understand that your MacBook Air upon startup at around the 50% progress bar, displays a "Reset Password" when you never received the option to log in. I'll be happy to help and shed some light.
To help troubleshoot this behavior, I recommend restarting your Mac in safe mode. This helps verify your startup disk and attempts to repair directory issues and more. You can read more about safe mode and how to perform this step through this article: Use safe mode to isolate issues with your Mac Once that's completed, please restart your Mac as normal and see if you continue to experience the same behavior.
If it does, the next step is to restart your Mac in macOS Recovery and to use Disk Utility as it can help detect if there's an issue with the disk that can be repaired. Here's how to restart in macOS Recovery: About macOS Recovery For instructions on how to use Disk Utility, you can follow the steps outlined here: Repair a storage device in Disk Utility on Mac
Kind regards.