Hi,
Long story short. If the VM is not backed up after deletion cannot be restored. If it is backed up, it is a matter of who has access to the backup solution.
If you want to have higher security besides just permissions, you can use Key Vault to encrypt the VM. Of course that means that you need to secure the Key Vault permissions as well.
Please "Accept the answer" if the information helped you. This will help us and others in the community as well.