@Patrick Treichler Thanks for posting in our Q&A.
Based on my research, I didn't find that Apple has given the MDM feature about unlock SIM. What intune can do is based on which MDM feature Apple provided.
I have noticed that the Popup appears, but disappears immediately. It seems that the Safari blocked Pop-ups. It is suggested to try to also add built-in app "Settings" to this kiosk profile and then check if the setting "Block Pop-ups" is turned off in Settings > Safari.
If there is anything update, feel free to let us know.
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