In this paper, we investigate the asymptotic structure of gauge theories in
decelerating and spatially flat Friedmann-Lema\^itre-Robertson-Walker
universes. Firstly, we thoroughly explore the asymptotic symmetries of
electrodynamics in this background, which reveals a major inconsistency already
present in the flat case. Taking advantage of this treatment, we derive the
associated memory effects, discussing their regime of validity and differences
with respect to their flat counterparts. Next, we extend our analysis to
non-Abelian Yang-Mills, coupling it dynamically and simultaneously to a Dirac
spinor and a complex scalar field. Within this novel setting, we examine the
possibility of constructing Poisson superbrackets based on the covariant phase
space formalism.
