Restrict schema without roles

We have around 120-130 sites that we maintain and we are looking at moving those to a headless setup as we perform re-dev or develop sites for new clients.

The vast majority of these sites (probably in the realm of 95%) don't need the user count that would warrant us pushing the medium plan to have "real" roles. Is there some mechanism to allow us to disable schema changes through the UI?

EDIT: For context we don't currently use Prismic and we are still evaluating 3-4 options for a headless provider.

Hello Jared. There's no way to restrict users from editing your custom types/schema on plans below the Medium plan. All users will be "Admin" on the plans without user roles and will be able to access the whole repo including the custom types/schema as well as the settings of the account. Let me know if you have further questions. Noor