Because Mint is based on Ubuntu, you can actually install the qubes
packages for Ubuntu and get a pretty seamless Qubes experience.
I’ve done this in the past.
If you want to try this, I provide prebuilt Ubuntu packages at
https://qubes.3isec.org
Make sure you match the package to the underlying Ubuntu version.
I suggest you clone the HVM that you install, and try this on the cloned
version - that way if things go wrong you will have a clean version to
fall back on.
At a minimum you should be able to get the core Qubes tools working -
qvm-copy etc.
I used to offer a Mint template - I’ll dust that off and rebuild it if
anyone wants it.