  In this work we investigate the prospect of observing new-physics signatures
via $C\!P$ violation in $\eta^{(\prime)}\to\pi^0\mu^+\mu^-$ and
$\eta^\prime\to\eta\mu^+\mu^-$ decays at the REDTOP experiment. We make use of
the SMEFT to parametrise the new-physics $C\!P$-violating effects and find that
the projected REDTOP statistics are not competitive with respect to nEDM
experiments. This reasserts the $\eta\to\mu^+\mu^-$ process as the most
promising channel to find $C\!P$-violation at this experimental facility.
