  In this work, we investigate the black hole (BH) population of globular
clusters (GCs) in Milky Way- (MW) and Andromeda- (M31) like galaxies. We
combine the population synthesis code MASinGa and the MOCCA-Survey Database I
to infer the properties of GCs harbouring a BH subsystem (BHS), an IMBH, or
neither of those. We find that the typical number of GCs with a BHS, an IMBH,
or none become comparable in the galactic outskirts, whilst the inner galactic
regions are dominated by GCs without a significant dark component. Our models
suggest that GCs harbouring a BHS are slightly heavier and with larger
half-mass radii compared to the overall population. We retrieve the properties
of binary BHs (BBHs) that have either merged in the last 3 Gyr or survived in
their parent cluster until present-day. We find that around 80\% of the merging
BBHs form due to dynamical interactions while the remaining originate from
evolution of primordial binaries. We infer a merger rate for BBHs in the local
Universe of $1.0-23\,\,\rm{yr^{-1}\,Gpc^{-3}}$, depending on the adopted
assumptions. We find around 100-240 BBHs survive until present-day and are
mostly concentrated in the inner few kpc of the galaxy. We estimate also the
number of BHs transported into the galactic nucleus by infalling star clusters,
finding around 1,000-3,000 BHs and 100-200 BBHs are transported over a time
span of 12 Gyr. This enables us to constrains the total amount of BHs and BBHs
binaries lurking in nuclear star cluster, i.e. $N_{BHs}=(1.4-2.2)\times10^4$
and $N_{BBHs}=700-1,100$.
