Struggling to find a guide to do this. I've understood that xen-tools supports installing Ubuntu guests on Debian so that should be a fast and easy way but can't find any examples.
Anybody knows a good guide to help me? Is it mandatory to use HVM for installation?
Figured out in the end, it seems that xen-create-image --dist=focal [...] is available in the latest xen-tools version so you can go with debootstrap installation method. However, Debian 10 has an older version which only supports Ubuntu up to 19.
So, the easy thing to do is install xen-tools from sources as this is just a simple collection of scripts: https://github.com/xen-tools/xen-tools.