  Experimental data suggest that the Higgs potential has a lower ground state
at high field values. Consequently, decaying from the electroweak to the true
vacuum nucleates bubbles that expand rapidly and can have dire consequences for
our Universe. This overview of our last study [1] regarding the cosmological
implications of vacuum metastability during Starobinsky inflation was presented
at the HEP2023 conference. Following the framework established in [2], we
showcased our state-of-the-art lower bounds on the non-minimal coupling $\xi$,
which resulted from a dedicated treatment of the effective Higgs potential in
$R+R^2$ gravity. The effects of this consideration involved the generation of
destabilising terms in the potential and the sensitive dependence of bubble
nucleation on the last moments of inflation. In this regime, spacetime deviates
increasingly from de Sitter and thus the validity of our approach reaches its
limit, but at earlier times, we recover our result hinting against eternal
inflation.
