If this universe is just 13.7 billion years old which is an incredibly short period in an infinite time possibility isn't a binary finishing universe say one charge positive and one negative also a valid start.

The two would not collide as such but be rapidly rotating as the event horizons came together.
It is possible the mass contained within each super singularity would be at a great distance from the Schwartzchild radius.

When these horizons meet or form an equilibrium, gravity is cancelled and instantly a potential Planck time interval. Nett effect nil gravity and releases both charged new universes, pure conservation.

The release would have the effect of flipping their charge and starting a cyclical set of thermodynamically conserved paired universes equal but opposite in charge and perfectly balanced in electron to proton ratio.

Cheers