Hello @Christopher Bagge , Do you have any OS or Data disks attached to this VM/Demo environment? Is it a Premium/Managed Disk? The Microsoft.compute/disk namespace suggests you have an attached disk which explains why you may still be incurring charges even though the VMs are stopped-deallocated.
Here's how you can check & remove the disk if (any) no longer needed. Please note this doesnt delete the underlying storage account.
Carefully read and follow the storage account deletion steps if needed.
Dont hesitate to ping if you have any followup questions.
Cheers.