Fraction of BCOs with WR–CO progenitors evolved through different formation channels for different metallicities (rows) and combinations of CCSN and natal kick models explored in this work (Table 1). Here, we show the α_CE = 3 case. We distinguish four main evolutionary paths based on mass transfer events that occurred before the WR–CO formation: stable mass transfer only, CEs only, at least one stable and one unstable mass transfer, no mass transfer. Hatched bars indicate WR–CO systems that become BCOs experiencing at least one additional mass transfer event (stable or unstable RLO) after the WR–CO phase.