How to mount raw btrfs Image backups with server running in docker

I recently set up a urbackup server in docker since I’m using btrfs as the storage I uncommented this in the docker-compose.yml

    cap_add:
      - SYS_ADMIN

I was succefully able to create both file and image backups for my PC and they seem to be stored as btrfs subvolumes as intented, however I see no option to mount the image backups I made, when I look at the log I see these lines related to image mounting

TEST FAILED: guestmount is missing (libguestfs-tools)
2024-09-16 21:20:19: Image mounting disabled: TEST FAILED: guestmount is missing (libguestfs-tools)

Whatever gusetmount or libguestfs-tools seems to be missing and it looks like that that’s required for image mounting. If guestmount needs to be installed for image mounting to work then why isn’t it already installed in the docker image? Do I need to enable something somewhere or do I need to build a custom docker image with guestmount installed to get this to work, or is that somthing that just dosn’t work in docker?