  We present the stellar metallicities and multi-element abundances (C, Mg, Si,
Ca, Ti, Cr, and Fe) of 15 massive (log M/M$_\odot$=10.2-11.2) quiescent
galaxies at z=1-3, derived from ultradeep JWST-SUSPENSE spectra. Compared to
quiescent galaxies at z~0, these galaxies exhibit a deficiency of 0.25 dex in
[C/H], 0.16 dex in [Fe/H], and 0.07 dex in [Mg/H], implying rapid formation and
quenching before significant enrichment from asymptotic giant branch stars and
Type Ia supernovae. Additionally, we find that galaxies that form at higher
redshift have higher [Mg/Fe] and lower [Fe/H] and [Mg/H], irrespective of their
observed redshift. The evolution in [Fe/H] and [C/H] is therefore primarily
explained by lower redshift samples naturally including galaxies with longer
star-formation timescales. On the other hand, the lower [Mg/H] can be explained
by galaxies forming at earlier epochs expelling larger gas reservoirs during
their quenching phase. Consequently, the mass-metallicity relation, primarily
reflecting [Mg/H], is also lower at z=1-3 compared to the lower redshift
relation, though the slopes are similar. Finally, we compare our results to
standard stellar population modeling approaches employing solar abundance
patterns and non-parametric star-formation histories (using Prospector). Our
SSP-equivalent ages agree with the mass-weighted ages from Prospector, while
the metallicities disagree significantly. Nonetheless, the metallicities better
reflect [Fe/H] than total [Z/H]. We also find that star-formation timescales
inferred from elemental abundances are significantly shorter than those from
Prospector, and we discuss the resulting implications for the early formation
of massive galaxies.
