The PIP-II complex at Fermilab is slated for operation later this decade and can support a MW-class O(1 GeV) proton fixed-target program in addition to the beam required for DUNE. Proton collisions with a fixed target could produce a bright stopped-pion neutrino source. The addition of an accumulator ring allows for a pulsed neutrino source with a high duty factor to suppress backgrounds. This source supports a program to search for new physics particularly in the dark sector, such as sensitive searches for accelerator-produced light dark matter, active-to-sterile neutrino oscillations, and other models such as axion-like particles (ALPs). A key feature of the PIP2-BD program is the ability to design the detector hall at Fermilab specifically for HEP physics searches. I will present the PIP-II project and upgrades towards a stopped-pion neutrino source at Fermilab and studies showing the sensitivities of the conceptual PIP2-BD detector, a O(100 ton) liquid argon scintillation detector to several dark sector models accessible with this source.