Top−left: the subhalo masses obtained by integrating the best modified NFW profile fits are plotted against the subhalo masses obtained from the particle data of the TNG50 simulation. The dashed orange line indicates where both masses are equal. Top−right: the mean relative errors of the subhalo masses obtained by integrating the best modified NFW profile fits are plotted against the true subhalo masses obtained from the simulation data for each mass bin. The standard deviations are indicated by the error bars. Bottom: Scaling of the Einstein radius (obtained by using the best modified NFW profile fits) with $M_{\mathrm{sub},\mathrm{mNFW}}\hspace{0.5em}{r}_{\mathrm{s}}^{-1}$. The colour-coding indicates the concentration c_V. The blue line shows the best power law fit.