  The recent NICER measurement of the radius of the neutron star PSR
J0740+6620, and the inferred small variation of radii from 1.4$M_\odot$ to
2.1$M_\odot$, reveal key features of the equation of state of neutron star
matter. The pressure rises rapidly in the regime of baryon density $n \sim$ 2-4
times nuclear saturation density, $n_0$ -- the region where we expect hadronic
matter to be undergoing transformation into quark matter -- and the pressure in
the nuclear regime is greater than predicted by microscopic many-body
variational calculations of nuclear matter. To incorporate these insights into
the microscopic physics from the nuclear to the quark matter regimes, we
construct an equation of state, QHC21, within the framework of quark-hadron
crossover (QHC). We include nuclear matter results primarily based on the
state-of-the-art chiral effective field theory, but also note results of using
nuclear matter variational calculations based on empirical nuclear forces. We
employ explicit nuclear degrees of freedom only up to $n \sim 1.5n_0$, in order
to explore the possibility of further physical degrees of freedom than
nucleonic here. The resulting QHC21, which has a peak in sound velocity in
$\sim 2$-$4 n_0$, is stiffer than the earlier QHC19 below 2$n_0$, predicting
larger radii in substantial agreement with the NICER data.
