Measurements of the branching fractions of ${\eta }_{c}\to {K}^{+}{K}^{-}{\pi }^{0}$, ${K}_{S}^{0}{K}^{±}{\pi }^{\mp }$, $2\left({\pi }^{+}{\pi }^{-}{\pi }^{0}\right)$, and $p\overline{p}$

Using data samples collected with the BESIII detector at center-of-mass energies $\sqrt{s}=4.23$, 4.26, 4.36, and 4.42 GeV, we measure the branching fractions of ${\eta }_{c}\to {K}^{+}{K}^{-}{\pi }^{0}$, ${K}_{S}^{0}{K}^{±}{\pi }^{\mp }$, $2\left({\pi }^{+}{\pi }^{-}{\pi }^{0}\right)$, and $p\overline{p}$, via the process ${e}^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{h}_{c}$, ${h}_{c}\to \gamma {\eta }_{c}$. The corresponding results are $\left(1.15±0.12±0.10\right)%$, $\left(2.60±0.21±0.20\right)%$, $\left(15.2±1.8±1.7\right)%$, and $\left(0.120±0.026±0.015\right)%$, respectively. Here the first uncertainties are statistical, and the second ones systematic. Additionally, the charged track multiplicity of ${\eta }_{c}$ decays is measured for the first time.