  Very recently, the Belle~II Collaboration presented a measurement for the
decays $B^+\to\bar{D}^{(*)0} K^+\bar{K}^0$ and $B^0\to D^{(*)-}K^+\bar{K}^0$,
the bulk of observed $m(K^+ K_S^0)$ distributions showing low-mass structures
in all four channels. In this work, we study the contributions of
$\rho(770,1450)^+$, $a_2(1320)^+$ and $a_0(980,1450)^+$ resonances to these
decay processes. The intermediate states $\rho(770,1450)^+$ are found to
dominate the low-mass distribution of kaon pairs roughly contributing to half
of the total branching fraction in each of the four decay channels. The
contribution of the tensor $a_2(1320)^+$ meson is found to be negligible. Near
the threshold of the kaon pair, the state $a_0(980)^+$ turns out to be much
less important than expected, not being able to account for the enhancement of
events in that energy region observed in the $B^+\to\bar{D}^{(*)0}
K^+\bar{K}^0$ decays. Further studies both from the theoretical and
experimental sides are needed to elucidate the role of the non-resonant
contributions governing the formation of $K^+\bar{K}^0$ pairs near their
threshold in these decay processes.
