  We investigate the influence of repulsive vector interactions and color
superconductivity on the structure of neutron stars using an extended version
of the field correlator method (FCM) for the description of quark matter. The
hybrid equation of state is constructed using the Maxwell description, which
assumes a sharp hadron-quark phase transition. The equation of state of
hadronic matter is computed for a density-dependent relativistic lagrangian
treated in the mean-field approximation, with parameters given by the SW4L
nuclear model. This model described the interactions among baryons in terms of
$\sigma, \omega, \rho, \sigma^*$, and $\phi$ mesons. Quark matter is assumed to
be in either the CFL or the 2SC+s color superconducting phase. The possibility
of sequential (hadron-quark, quark-quark) transitions in ultra-dense matter is
investigated. Observed data related to massive pulsars, gravitational-wave
events, and NICER are used to constrain the parameters of the extended FCM
model. The successful equations of state are used to explore the mass-radius
relationship, radii, and tidal deformabilities of hybrid stars. A special focus
lies on investigating consequences that slow or fast conversions of
quark-hadron matter have on the stability and the mass-radius relationship of
hybrid stars. We find that if slow conversion should occur, a new branch of
stable massive stars would exist whose members have radii that are up to 1.5~km
smaller than those of conventional neutron stars of the same mass. Such objects
could be possible candidates for the stellar high-mass object of the GW190425
binary system.
