@Justin S. Lee , Thanks for posting again in our Q&A. In General, Enroll with User Affinity is used for the scenario that the device belong to users who wants to use Company Portal for services like installing apps. Enroll without User Affinity is used for the scenario that the device is used for kiosk, point of sale (POS), or shared-utility. For our situation, we suggest to choose with user affinity. Here is an article with more details for the reference:
https://learn.microsoft.com/en-us/mem/intune/enrollment/device-enrollment-program-enroll-ios#create-an-apple-enrollment-profile
Hope it can help.
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