Redmine

We are using Redmine in a customer context where it is required that issues must never be physically deleted. Currently, issue deletion can be controlled via roles and permissions, but administrators still may have the permission to delete issues.
We would like to request an option (e.g. a global setting) to completely disable issue deletion for all users including administrators, so that issues can only be closed but never removed from the database.
This would help us meet compliance requirements and make Redmine more suitable for regulated environments.
Thank you!