  We model interaction with the surrounding medium of the main discrete jet
ejection in the accreting black-hole binary MAXI J1348--630. The kinetic energy
in the ejection of that jet was estimated before to be $>10^{46}$ erg. That
energy requires that the jet power was about two orders of magnitude above the
limit corresponding to a magnetically arrested accretion onto a maximally
rotating black hole. That large estimate was obtained by considering the
initial ballistic jet propagation in a surrounding cavity followed by a sudden
deceleration in interstellar medium under the assumption of its standard
density of $\sim$1 cm$^{-3}$. Such densities are likely in the surrounding of
this source given its location in the Galactic Plane. Here, we show that the
estimate of the kinetic energy can be reduced to realistic values of $\sim\!
10^{44}$ erg by considering the presence of a transition layer with an
exponential density growth separating the cavity and the interstellar medium.
In that case, the jet is found to decelerate mostly in the transition layer, in
regions with the densities $\ll$1 cm$^{-3}$, which strongly reduces the energy
requirement. Still, the required jet masses are large, ruling out the presence
of a significant number of electron-positron pairs.
