The information I can find on the Lima airport testing facility is here.
https://unilabs.joinnus.com/ But it says they are only open from 5:00AM to 5:00PM. I have seen various official sources saying that the 14 day quarantine can be waived with a negative antigen test within 24 hours of arrival but I have not seen exactly how the mechanics of that works in practice. It is implied, but not specifically stated, that a traveler could just get tested at any approved lab within 24 hours of arrival. But the details of that seem a bit foggy.
In any case I'll be able to update in a few weeks one way or another.
Big thanks for the information
andreadbc provided.