Excellent post I have always been attracted to these topics of Physics @lemouth.

Regarding the following:

Calculations have shown that baryonic dark matter with a mass close to the one of the proton and the neutron do not allow neutron stars that are heavier than the sun to exist.
This is however in conflict with the observations... here are way out, but theories are becoming more complicated.

Particularly I think, that as science delves into the more exotic forms of matter, the theories will be even more complicated.