AMIs/Volumes for Debian should not be restricted to Marketplace codes
The AMI is awesome, but it's quite annoying to be unable to mount the volume on another running instance to fix something. One must stop the second instance only to be able to mount the marketplace-coded volume and then work from there to sort a problem out.
Note that these AMIs are also available as "Community AMIs" outside the Marketplace. Community AMIs won't have the problem you describe. Find them at https://wiki.debian.org/Cloud/AmazonEC2Image/Buster