  Quasi-periodic eruptions (QPEs) are repeated X-ray flares from galactic
nuclei. Despite some diversity in the recurrence and amplitude of eruptions,
their striking regularity has motivated theorists to associate QPEs with
orbital systems. Among the known QPE sources, eRO-QPE2 has shown the most
regular flare timing and luminosity since its discovery. We report here on its
long-term evolution over $\sim3.3\,$yr from discovery and find that: i) the
average QPE recurrence time per epoch has decreased over time, albeit not at a
uniform rate; ii) the distinct alternation between consecutive long and short
recurrence times found at discovery has not been significant since; iii) the
spectral properties, namely flux and temperature of both eruptions and
quiescence components, have remained remarkably consistent within
uncertainties. We attempted to interpret these results as orbital period and
eccentricity decay coupled with orbital and disk precession. However, since
gaps between observations are too long, we are not able to distinguish between
an evolution dominated by just a decreasing trend, or by large modulations
(e.g. due to the precession frequencies at play). In the former case, the
observed period decrease is roughly consistent with that of a star losing
orbital energy due to hydrodynamic gas drag from disk collisions, although the
related eccentricity decay is too fast and additional modulations have to
contribute too. In the latter case, no conclusive remarks are possible on the
orbital evolution and the nature of the orbiter due to the many effects at
play. However, these two cases come with distinctive predictions for future
X-ray data: in the former, we expect all future observations to show a shorter
recurrence time than the latest epoch, while in the latter we expect some
future observations to be found with a larger recurrence, hence an apparent
temporary period increase.
