  We explore the system size dependence of heavy-quark-QGP interaction by
studying the heavy flavor meson suppression and elliptic flow in Pb-Pb, Xe-Xe,
Ar-Ar and O-O collisions at the LHC. The space-time evolution of the QGP is
simulated using a (3+1)-dimensional viscous hydrodynamic model, while the
heavy-quark-QGP interaction is described by an improved Langevin approach that
includes both collisional and radiative energy loss inside a thermal medium.
Within this framework, we provides a reasonable description of the $D$ meson
suppression and flow coefficients in Pb-Pb collisions, as well as predictions
for both $D$ and $B$ meson observables in other collision systems yet to be
measured. We find a clear hierarchy for the heavy meson suppression with
respect to the size of the colliding nuclei, while their elliptic flow
coefficient relies on both the system size and the geometric anisotropy of the
QGP. Sizable suppression and flow are predicted for both $D$ and $B$ mesons in
O-O collisions, which serve as a crucial bridge of jet quenching between large
and small collision systems. Scaling behaviors between different collision
systems are shown for heavy meson suppression factor and the
bulk-eccentricity-rescaled heavy meson elliptic flow as functions of the number
of participant nucleons in heavy-ion collisions.
