Use podman for containers
My thoughts
I noticed that for graft application the demo seems to show LXC and full virtual machines. I think this design will cause a large amount of headaches and it would be simpler to just use podman.
What is podman
Podman is a container runtime that runs as the local user with low overhead. It is very fast and makes creating and destroying containers very easy.
Where are my thoughts coming from
On my devices I use a tool called distrobox. Distrobox uses podman by default and creates small containers that allows for quick distro specific environments.
This issue as it relates to the project
For flatpak support you could create a default debian podman container that has flatpak setup with a app store installed in the container. This would allow users to I stall any flatpak without needing to have any Linux knowledge.
I would love to contribute to this but I don't really know how.