@Charlie Scoccia, Thanks for posting in our Q&A.
From your description, I know you want to force company users to only use one web browser on iOS device via Intune.
Based on my research, organizations can use Azure AD Conditional Access policies to ensure that users can only access work or school content using Edge for iOS. For more details, please refer to the following article:
https://learn.microsoft.com/en-us/mem/intune/apps/manage-microsoft-edge#apply-conditional-access
It is suggested to try to create an app protection policy and add Edge as a managed app in it. Then refer to the following steps to configure conditional access policy.
https://learn.microsoft.com/en-us/entra/identity/conditional-access/howto-policy-approved-app-or-app-protection#require-approved-client-apps-or-app-protection-policy-with-mobile-devices
Hope it will give you some ideas.
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