Lore provided by OP
My headcanon is that this far in the future, mankind has spread to the stars to such an extent that many/most of us have lost knowledge of where Earth is/was. After a certain point in history, the optimism fades, people start getting nostalgic for their roots, and there's a sudden resurgence of interest in recovering what was lost. The Harkema Salvage Combine was founded with that mission, recovering and reassembling what's been lost, specifically with a focus on lost ancient technology, but their mission has drifted somewhat to include all lost wisdom and knowledge and lore generally. This world, Aphros, was among the first colonized by the out-pouring wave of human settlers, and the crew that founded Aphros Station is hopeful they'll be able to find hints as to Earth's whereabouts among the layers of ancient technology found here. Each of the original crew were misfits of various sorts. Ethan Noir, the leader, comes from an untrustworthy and greedy itinerant merchant class, and left because he grew fed up with their treacherous ways. Octavian, his second-in-command, was a member of a deeply insular spacefaring society consciously modeled on pagan Rome, with pagan Roman gods, dress, and Latin; this society is so insular that until Octavian left and joined up with the Combine, the Combine had forgotten the meaning of its own motto ("Ignem Portamus" - "we carry the flame"), of which Octavian had to remind them. Anne, the tech chief, was a member of a nomadic glitterworld-style fleet of ships that experienced massive civilizational collapse when she was 14, plunging them into Balkan war-style conditions practically overnight. She escaped and joined up with the Combine solely because they were the first ones to wander past her hellship when she figured out a means of escaping. Bitter and untrusting and hard as hell, her time with the boys (good and honorable men both) eventually softened her up. Others joined later, after the Station was founded, but the three share fond memories of living in a tiny square hut erected over a steam geyser while they tunneled out a base into the side of the mountain.
All this I mean to write as a book some day. The ultimate artifact they find is a digital recording of Morten Lauridsen's "O Magnum Mysterium", which they hear, listen to, and are moved by, even though none of them understand what it means (not even Octavian, and it's written in his own language). When they are able to date it to just a few centuries before the start of the Stellar Diaspora, they realize they must be close to Earth, and set off full of hope, eager to find out the meaning of this "Great Mystery" of which the choir was singing.