  We demonstrate a single-parameter route for reproducing higher mass objects
as observed in the LIGO--Virgo mass distribution, using only the isolated
binary stellar evolution channel. This single parameter encodes the
cosmological mass growth of compact stellar remnants that exceed the
Tolman-Oppenheimer-Volkoff limit. Cosmological mass growth appears in known
solutions to General Relativity with cosmological boundary conditions. We
consider the possibility of solutions with cosmological boundary conditions,
which reduce to Kerr on timescales short compared to the Hubble time. We
discuss complementary observational signatures of these solutions that can
confirm or invalidate their astrophysical relevance.
