Excluded pulsar/magnetar parameter space for three cases: negligible ejecta absorption (black), ejecta properties corresponding to the best-fit M_ej and v_ej inferred from optical data for SN 2018bsz (magenta; S. Gomez et al. 2024), and a minimum-absorption scenario defined by the lowest M_ej and highest v_ej within the 1σ confidence intervals (blue; S. Gomez et al. 2024). All lines are derived from the XMM luminosity limit in 2–10 keV assuming the average Cont.A. The black line is derived from the pulsar models in Equations (1)–(3), and the others are based on ionization breakout following Equations (1) and (4) of R. Margutti et al. (2018). The green cross shows the BP_optical, and the green box is the corresponding 1σ spread.