  Topological superfluids protected by mirror and time-reversal symmetries are
exotic states of matter possessing Majorana Kramers pairs (MKPs), yet their
realizations have long been hindered by the requirement of unconventional
pairing. We propose to realize such a topological superfluid by utilizing
$s$-wave pairing and emergent mirror and time-reversal symmetries in two
coupled 1D ultracold atomic Fermi gases with spin-orbit coupling. By stacking
such systems into 2D, we discover topological and Dirac-nodal superfluids
hosting distinct MKP flat bands. We show that the emergent symmetries make the
MKPs and their flat bands stable against pairing fluctuations that otherwise
annihilate paired Majoranas. Exploiting new experimental developments, our
scheme provides a unique platform for exploring MKPs and their applications in
quantum computation.
