The new version of the Li\`ege intranuclear-cascade model (INCL), recently extended to the production of strange particles and hypernuclei, is used to investigate the $\mathrm{\ensuremath{\Lambda}}$-nucleus potential in a broad range of nuclear masses from Si to Pb. The combination of the INCL calculation results with experimental cross sections of $\mathrm{\ensuremath{\Lambda}}$ hypernuclei, obtained from (${\ensuremath{\pi}}^{+},{K}^{+}$) reaction studies, allows us to constrain the $\mathrm{\ensuremath{\Lambda}}$-nucleus potential depth with an accuracy of about 0.9 MeV. Our results show that the potential depth increases with the mass number ($A$) from 28 MeV in the region of medium-mass hypernuclei up to a maximum of 39.6 MeV in the region of heavy hypernuclei around $A=208$. This deviation could be related to the nucleon-isospin dependence of the three-body $\mathrm{\ensuremath{\Lambda}}$-nucleon-nucleon force in asymmetry matter whose contribution is more relevant in hyperneutron matter due to a strong contribution from $\mathrm{\ensuremath{\Lambda}}nn$ interactions.