If I understand you correctly, you would like to have your local AD accounts connected to Azure AD. First you will need Azure AD Connect (hybrid):
Next, you will no longer use GPOs (from local) for Intune. You can convert a lot to most of the templates that are out there in Intune already. For the things that require some programming (PowerShell) I recommend you create scripts or win32 wrapped apps:
https://learn.microsoft.com/en-us/mem/intune/apps/apps-win32-app-management
Hope this helps.
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