Delay times of mergers in the GW231123 mass CI for different cluster environments in our simulations. The filled histograms refer to Z = 0.002 runs, while the empty histograms refer to Z = 0.0002 runs. In the latter case, the solid lines refer to primary BHs undergoing a single merger event (“Stellar”), while the dashed lines refer to BHs that also underwent previous mergers (“Hierarchical”).