Just a little question... Does zink come intalled by default on Solus, or do I have to compile it from source?

We don't build Zink with mesalib because there's currently no reason to. Zink is primarily designed for platforms that only have Vulkan support and not OpenGL and is not yet working well enough to be considered for day-to-day use.

We don't make a habit out of enabling things just for the sake of doing so. It bloats individual packages and a pattern of doing so will bloat both user systems and ISOs, not to mention it increases compile time and the surface area for bugs to be introduced.