@CactusCake Thanks for posting in our Q&A.
For intune Configuration Profile Remove issue, whether the setting keeps the existing value or revert back to a default value, it depends on its CSP.
https://learn.microsoft.com/en-us/mem/intune/configuration/device-profile-assign
Based on my research, I find that Personalization CSP's supported operations are Add, Get, Delete, and Replace.
https://learn.microsoft.com/en-us/windows/client-management/mdm/personalization-csp
It is suggested to try to remove the group in assignments' included groups and add the group in excluded groups. Then sync the device and check if the profile is removed from the device.
Hope it will give you some ideas.
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