You should definitely check for "aws-reserved" and "aws-service-role" in the ARN of the role you consider deleting. Service-Linked Roles and Roles for SSO will contain these prefixes in their ARN's.
However, I would rather recommend you to attach tags to the roles you create. You can then simply filter your roles by custom tags to make sure you only delete the Roles you created. Implementing Tag policies for your organization, will ensure that certain tags are set(https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_policies_tag-policies.html).
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