Can I get help with my iPad Activation Lock after domain capture?

My iPad became activation locked after moving my accounts from personal accounts to business accounts. My iPad shows my user as the user logged in but I cannot sign out and it keeps requesting me to sign in. Sign-in fails although I can sign into iCloud and other devices. Apple tells me the device is activation locked and there's nothing they can do. They hinted that the device is registered to the temp account created during the domain capture but wouldn't specifically tell me what user it was but my account doesn't show the device. Apple Business Manager doesn't show it either. Am I just screwed here? I purchased it refurbished years ago and been using it fine before the migration but the receipt doesn't show the serial number. Seems insane they can just lock my iPad and tell me to get lost.

[Edited by Moderator]