  One of the fundamental signatures of the Quark Gluon Plasma has been the
suppression of heavy flavor (specifically D mesons), which has been measured
via the nuclear modification factor, $R_{AA}$ and azimuthal anisotropies,
$v_n$, in large systems. However, multiple competing models can reproduce the
same data for $R_{AA}$ to $v_n$. In this talk we break down the competing
effects that conspire together to successfully reproduce $R_{AA}$ and $v_n$ in
experimental data using Trento+v-USPhydro+DAB-MOD. Then using our best fit
model we make predictions for $R_{AA}$ and $v_n$ across system size for
$^{208}PbPb$, $^{129}XeXe$, $^{40}ArAr$, and $^{16}OO$ collisions. We find that
0--10\% centrality has a non-trivial interplay between the system size and
eccentricities such that system size effects are masked in $v_2$ whereas in
30--50\% centrality the eccentricities are approximately constant across system
size and, therefore, is a better centrality class to study D meson dynamics
across system size.
