Sun is down, satellite internet is still up! Turns out there are few things more annoying than losing internet when the sun goes behind some object.
The DROK DC-DC booster solved it. I had originally planned to use it instead of the DC power supply, but that led to very loud coil whine not suitable for use. Don't understand why. Using the DROK to power an inverter, which then gets converted back to DC is not efficient, but at least it works. (And I tuned it so the inverter never spins its fan, so perhaps it's not super innefficient.)
Probably will switch to a better inverter that can handle lower voltages on its own.