Would it be a yes-or-no thing, or more of a continuum?
At stellar mass x there’s Some quark soup but it’s mostly ordinary neutronium, at 50x there’s More, at 10,000x there’s Pretty Much All Of It, etc?
Or is it a critical mass kind of thing where at stellar mass x there’s No Soup For You and at x+3 it’s a veritable soup buffet?
The latter, I suspect. That’s certainly how forming a neutron star works in the first place, because if a star gets so dense that it can form neutronium then the neutronium (which is far more dense than the core was before) can easily keep making more.
It’s a similar story with black holes. Get past the threshold at which it forms, and the process runs away and swallows the whole star.
If a quark soup is more dense than neutronium, then it would be fairly all-or-nothing
