T2 Got locked out of my own 2019 Macbook Pro?

*This is a rather peculiar situation as I got locked out of my own laptop. Keep in mind I'm in IT so I know what I'm doing.* **The setup:** I own a Macbook Pro 2019 with T2 (with purchase documents and so on). I don't use iCloud at all, never set it up, ever. 1. (classic)Filevault 2 was off. (or at least I never enabled it) 2. No firmware password. 3. T2 security was set to none and allow booting from USB. (I can boot Windows, Linux just fine) It's my machine so no security was needed. I have an admin account on it I know what the password is 100%. **The problem:** I used Migration Assistant to import some old user from an older mac. Encountered a bug where I couldn't delete the user completely (it's an obscure bug with users created in High Sierra) https://discussions.apple.com/thread/8087348?sortBy=best Rebooted and now Mac is in a reboot loop. **What doesn't work:** 1. I can hold Option (Alt) to see the drive and try to boot from it. (tries to boot restarts) 2. I can hold Cmd + R to try to get into Recovery. (tries to boot restarts) 3. I can hold download Internet Recovery. (tries to boot restarts) **What works:** I can put the Macbook Pro in DFU mode and tried to Revive. It works but has same symptoms. I don't want to Restore and Erase it, i think that would give me back the machine but trash the key on T2 losing the data. What's on it has enough sentimental value for me to just shelf the mac and wait for a solution. I can hold Option (Alt) and boot Windows setup, any linux distro (nixos...) etc but they have limited support for T2. I can boot into Target Disk Mode and with my other Mac connect to it asks for a password (none of my known passwords work). (I can access part of the drive like the EFI partition, Recovery and Preboot volume are unecypted) Apparently T2 enables encryption on the OS and Data volumes all the time, 'diskutil list' shows then as Encrypted No (encrypted at rest) and now can't boot and unlock the drive even though it was running fine before I restarted. **Conclusion:** Scraping in the Preboot volume which mounts as Read Only I found some info. The user i was trying to import has become the only user that can decrypt the drive with an "admin" password. With the user partially gone I'm thinking it has some problem decrypting the OS and Data Volumes. Somehow Preboot is no longer in sync with the actual setup. My family data is there I can't get to it. Ideas on what to try? From what I gather T2 should unlock the drive on boot, I think it tries, fails and resets. **Results so far:** Managed to unlock the drive on another machine via Target Disk Mode with the temporary password given during migration to the 'high sierra' non admin user. It says unlocked in terminal but it doesn't seem to mount. I restarted the machine fine a couple of times after the Migration completed so I'm thinking the failed mount has something to with the fact I tried to delete said user?