Dear James LaFlame,
Good day! Welcome to the Microsoft Q&A forum!
Based on your description, I understand that the BitLocker recovery key is accepted successfully, but the device reboots and returns to the BitLocker recovery screen. Since System Restore and the other troubleshooting options have already failed, Command Prompt may be worth trying.
From Troubleshoot > Advanced options > Command Prompt, first check the BitLocker status:
manage-bde -status
If your Windows drive is C:, try unlocking it with your recovery key:
manage-bde -unlock C: -RecoveryPassword YOUR-48-DIGIT-KEY
If it unlocks successfully, you can temporarily suspend BitLocker protectors:
manage-bde -protectors -disable C:
Then restart and select Continue to boot Windows.
I would avoid changing TPM, Secure Boot, or other BIOS settings for now, as these changes can trigger BitLocker recovery again.
If the issue persists, please share the output of manage-bde -status and whether the problem started after a BIOS, firmware, Windows, or hardware change. This will help determine the next troubleshooting step.
Thank you, and I look forward to your update.