I guess technically, Raspbian.
The Affinity Suite is great, but I’m suspicious of its acquisition by Canva—I’m afraid their solution to “bringing the suite to Linux” will be turning it into a web service.
Ok—to the extent that SVG is HTML, the variant of HTML that it is is a flavor of XML.
More precisely, both are flavors of XML.
The current version of Affinity is great and will continue to work forever—there’s no need to switch to an alternative if you’re already using it. I just don’t have much hope for its future development.