  $^{180m}$Ta is a rare nuclear isomer whose decay has never been observed. Its
remarkably long lifetime surpasses the half-lives of all other known $\beta$
and electron capture decays due to the large K-spin differences and small
energy differences between the isomeric and lower energy states. Detecting its
decay presents a significant experimental challenge but could shed light on
neutrino-induced nucleosynthesis mechanisms, the nature of dark matter and
K-spin violation. For this study, we repurposed the MAJORANA DEMONSTRATOR, an
experimental search for the neutrinoless double-beta decay of $^{76}$Ge using
an array of high-purity germanium detectors, to search for the decay of
$^{180m}$Ta. More than 17 kilograms, the largest amount of tantalum metal ever
used for such a search was installed within the ultra-low background detector
array. In this paper we present results from the first year of Ta data taking
and provide an updated limit for the $^{180m}$Ta half-life on the different
decay channels. With new limits up to 1.5 x $10^{19}$ years, we improved
existing limits by one to two orders of magnitude. This result is the most
sensitive search for a single $\beta$ and electron capture decay ever achieved.
