You manage this. We do not.
Apple allows user-approved MDM enrollment without wiping the iPhone. That path can push Level 1 / Level 2 later. It does not Supervise the device, so it cannot hide Instagram or apply the Level 4.2 keys (Siri / AirDrop / USB pairing / app blocks).
This is not the same as Level 3. Level 3 is Lockdown Mode in Settings. You can enroll here with Lockdown Mode on, or off. If Lockdown Mode is already on, enroll through your MDM URL — Safari will not install a new local profile.