How to remove myself from an MDM account imposed by a controlling ex-partner?

1. Try Manual Removal

Sometimes the profile isn't locked. Try this first:

 iPhone/iPad: Go to Settings > General > VPN & Device Management. Tap the MDM profile and check for a "Remove Profile" button.

 Mac: Go to System Settings > Privacy & Security > Profiles. Select the MDM profile and click the "-" (minus) button.

2. Factory Reset (DFU Restore)

If manual removal is blocked, you must completely wipe the device.

 Important: Do not restore a full backup, or the MDM profile might return. Set up the device as "New" and sync only essential data (like photos and contacts) from iCloud.

3. The ABM (Apple Business Manager) Issue

If the device's serial number is registered in a corporate Apple account, the MDM lock will reinstall automatically after a reset.

 Solution: Only the account owner can release the serial number. Alternatively, you can contact Apple Support with your original proof of purchase to request a removal

If you read closely, I actually explained that if the profile was installed via ABM/DEP a factory reset won’t remove it. However, if it was installed manually (for instance, by downloading a configuration file from a web link or a third-party app, which is the typical scenario for stalkerware or non-corporate parental/personal control), a factory reset absolutely removes the MDM.

This happens because the profile lives solely within the local operating system: wiping the device's content deletes the profile along with it.

• What MDM profile are you referring to when viewed at Settings > General > VPN & Device Management?
• Controls can be placed on your device using Family Sharing where your GF is listed as an Organizer or with administrative rights and that would be found if you have a Family listed when opening the Settings app.
• Screen Time controls can also be placed on your device with physical access to it with anyone knowing the Passcode. Check if you have a Screen Time Passcode enabled at Settings > Screen Time.
• Despite what you were told previously a Factory Reset does not remove a MDM unless at has been previously released by the Administrator of the MDM.

need to erase and reset my ipad that is m… - Apple Community

Remove MDM from iPhone 13 - Apple Community

Beyond that describe what you are not able to do on your phone and provide a Screenshot as long as it does not reveal any personal information.

Unless your gf is a manager at a company where she can access the MDM software and had unrestricted access to your device for a considerable amount of time so she could add it to the MDM, or, spend a considerable amount of money on an MDM just to troll you, it seems unlikely your iPhone is actually tied to an MDM account.

It's more likely she's applied Screen Time restrictions over Family Sharing than actually adding an MDM profile to your device.

If you explain exactly what is happening on your device that makes you think it's tied to an MDM we may be able to offer a course of action.

And if you pay attention, you'll see that Mac Jim ID was not talking to you.