Self-hosted artifact installation policies

Hello, I hope my question fits here

I am responsible for maintenance and administration of a self-hosted GitLab instance in my company, which we set up on a k8s cluster.
Being a bit low on storage, I set the instance level expiration for artifacts to 3 hours, but it seems like some artifacts are not being deleted, and some are also staying “forever”

I would like to know, is artifacts not being deleted some kind of bug that should not be happening? Or this due to clients setting their ci’s expire_in to some value that then takes priority over the instance level? Is there any way to limit artifacts sizes and project storage?