Different Retention Policies for Active/Inactive Mailboxes

You do not have the required licensing to use Purview adaptive scopes. The official documentation states

If the retention policy uses an adaptive policy scope, then one of the following licenses is required to provide user rights:

• Microsoft 365 E5/A5/G5
• Microsoft Purview Suite/EDU/GOV/FLW and Microsoft Defender + Purview Suite FLW
• Office 365 E5/A5/G5
• Microsoft 365 E5/A5/F5/G5 Information Protection and Governance

See Microsoft Purview service description - Service Descriptions | Microsoft Learn.

For testing, make sure you have an active user with a license.

Check that they are in the adaptive scope of the active user

Then check that the active retention policy is applied to the user (this can take up to 7 days to apply)

Only once this is confirmed can you delete the user.

The user should switch to the inactive users' adaptive scope and switch retention policies. Again, this may take a week.  

Patience is required when testing retention policies and labels.

I do not have a GCC tenant, but this is the adaptive scope query I  use. 

RecipientTypeDetails -eq "UserMailbox" -and IsInactiveMailbox -eq "True"