Bolometric light curve models simulated with SNEC without CSM for 2, 3, and 4 M_⊙ stripped masses and fixed explosion energy and ⁵⁶Ni masses of 1.3 × 10⁵¹ erg and 0.08 M_⊙, respectively, are shown along with the observed light curves in the top panel. The shaded region indicates the time frame used to constrain the extent of mass stripping in the progenitor model. In the bottom panel, the model photospheric velocities are compared to the expansion velocity of SN 2021tsz, derived from the minima of the Fe IIλ5169 absorption line.