  Sizeable exotic Higgs boson production through gluon fusion via top quark
loops is correlated with large Higgs decay probabilities into top quark final
states, if these are kinematically accessible. It is known that $gg\to S \to
t\bar t$ is particularly susceptible to signal-background interference effects
that can significantly impact discovery sensitivities. In such an instance,
identifying more robust signatures to enhance the discovery sensitivity becomes
necessary, shifting phenomenological focus to final states that show a reduced
destructive signal-background interference. In this work, we discuss the
phenomenological relevance of signal-signal and signal-background interference
effects for decay chains. In particular, we identify asymmetric cascade decays
in models of scalar extensions of the SM Higgs sector as new promising
candidates. In parallel, characteristic interference patterns can provide a
formidable tool for indirect CP spectroscopy of BSM sectors if a discovery is
made in the future. This motivates associated searches at present and future
colliders as robust discovery modes of new physics, in addition to serving as a
sensitive tool for the reconstruction of the underlying UV electroweak
potential.
