  This article presents constraints on dark-matter-electron interactions
obtained from the first underground data-taking campaign with multiple
SuperCDMS HVeV detectors operated in the same housing. An exposure of 7.63
g-days is used to set upper limits on the dark-matter-electron scattering cross
section for dark matter masses between 0.5 and 1000 MeV/$c^2$, as well as upper
limits on dark photon kinetic mixing and axion-like particle axioelectric
coupling for masses between 1.2 and 23.3 eV/$c^2$. Compared to an earlier HVeV
search, sensitivity was improved as a result of an increased overburden of 225
meters of water equivalent, an anticoincidence event selection, and better
pile-up rejection. In the case of dark-matter-electron scattering via a heavy
mediator, an improvement by up to a factor of 25 in cross-section sensitivity
was achieved.
