Expected distributions of donor stars in H-R diagram for models B1, B2, B3, and BHL at Z = Z_⊙ (upper panel), 0.2 Z_⊙ (middle panel), and 0.02 Z_⊙ (lower panel), respectively. The color represents the number of wind-fed NS ULXs (i.e., L_X >  10³⁹ erg s⁻¹) in each matrix element. The cross is the location of the red supergiant donor star in PULX NGC 300 ULX-1. The labels B1, B2, B3, and BHL in the panels represent WRLOF models with β = 1 (B1), β = 2 (B2), β = 3 (B3), and BHL models, respectively. For example, the model B1/Z = Z_⊙ represents the WRLOF model with β = 1 (B1) and Z = Z_⊙.