I have a tenant with 2 environments - one is the Default environment (with a CDS database) and the other a Production Dynamics 365 environment. I have noticed that when administering security from https://admin.powerapps.com the security is now directed through Dynamics 365 security roles instead of the Environment Admin and Environment Maker environment roles. The environment roles do not appear for the Default and Production Dynamics 365 environments.
RE "When I access the security roles I can turn off the Environment Maker user role. "
If you are trying to remove 'Environment Maker' privileges for the user in the Default environment, please note that this cannot be removed. If this is within an production environment this should not be the case, unless they also have System Administrator privileges.
RE "The environment roles do not appear for the Default and Production Dynamics 365 environments."
I have done some more investigation on this and have found that a PowerApps environment without a CDS instance has a different security screen to a PowerApps environment with CDS. Please see the two attachments. My Default environment and Dynamics 365 both have a CDS instance and I can only update security through the Dynamics 365 user management center. Removing the Environment Maker role in the Dynamics 365 user management center for my Dynamics 365 environment only seems to remove the ability for a user to create Model-driven apps. They can still create canvas apps and Flows etc.
Thanks for your help. I will send you my environment IDs via email.