This is the gold standard for most users. Blender itself is open-source and free, and the community-developed "XPS Tools" add-on is the most powerful converter available.
: Many XPS models are fan-made. Ensure you have permission if you're using them for anything beyond personal practice. xps 3d model converter free
Blender is not a converter by default—it is a full DCC (Digital Content Creation) suite. However, with the free community add-on (often built into Blender 3.x+ under "Import"), you can open XPS directly. This is the gold standard for most users