  Unconventional flat band (FB) superconductivity, as observed in van der Waals
heterostructures, could open promising avenues towards high-T$_c$ materials. In
FBs, pairings and superfluid weight scale linearly with the interaction
parameter, such an unusual behaviour justifies and encourages strategies to
promote FB engineering. Bipartite lattices (BLs) which naturally host FBs could
be particularly interesting candidates. Within Bogoliubov de Gennes theory and
in the framework of the attractive Hubbard model in BLs, a hidden symmetry of
the quasi-particle eigenstates is revealed. As a consequence, we demonstrate
universal relations for the pairings and the superfluid weight that are
independent of the characteristics of the hopping term. Remarkably, it is shown
that these general properties are insensitive to disorder as long as the
bipartite character is protected.
