  The result of a search for the pair production of the lightest supersymmetric
partner of the bottom quark ($\tilde{b}_{1}$) using 139 fb$^{-1}$ of
proton-proton data collected at $\sqrt{s} = 13$ TeV by the ATLAS detector is
reported. In the supersymmetric scenarios considered both of the bottom-squarks
decay into a $b$-quark and the second-lightest neutralino, $\tilde{b}_{1}
\rightarrow b + \tilde{\chi}^{0}_{2}$. Each $\tilde{\chi}^{0}_{2}$ is assumed
to subsequently decay with 100% branching ratio into a Higgs boson ($h$) like
the one in the Standard Model and the lightest neutralino:
$\tilde{\chi}^{0}_{2} \rightarrow h + \tilde{\chi}^{0}_{1}$. The
$\tilde{\chi}^{0}_{1}$ is assumed to be the lightest supersymmetric particle
(LSP) and is stable. Two signal mass configurations are targeted: the first has
a constant LSP mass of 60 GeV; and the second has a constant mass difference
between the $\tilde{\chi}^{0}_{2}$ and $\tilde{\chi}^{0}_{1}$ of 130 GeV. The
final states considered contain no charged leptons, three or more $b$-jets, and
large missing transverse momentum. No significant excess of events over the
Standard Model background expectation is observed in any of the signal regions
considered. Limits at the 95% confidence level are placed in the supersymmetric
models considered, and bottom-squarks with mass up to 1.5 TeV are excluded.
