"The survey team’s last contact filled me with elation … and dread"
Hmm, I'm of a mind of my obsession with Xenoarcheology and finding something interesting
on a former home to a Forerunner culture. Interesting as in "Oh my god, oh my god, we're all going to die."
Almost all forms of archeology and anthropology deal with sorting through trash looking for nuggets of interest. Barring ancient curses and various ancient Egyptians, the worse thing you could find is an old virus that still finds us tasty.
With alien Forerunner trash, you find things that can bring down your entire civilization. Or worse, you find something still working. Like a Great Machine or Ancient Doomsday Weapon. But in keeping with the prompt, the survey team has found a Krell Great Machine, and not a Star Trek Lead Pipe of Doom.
Now, I've talked about this before on our podcast, the series starts here: https://tritacsystems.podbean.com/e/epi ... -ftl-2448/
In this case, the players are a Xenoarcheological expedition sponsored by a big Interstellar Corporation koff
on an ancient Forerunner world. So far, all that they have found is Forerunner trash. 99% of all archeological finds are trash. (There are several branches of archeology devoted to the things you find in latrines and the contents of human coprolites.)
Poking around in some fairly intact ruins, maybe on the world's moon, they find that they are still operational and want to serve
its new masters. What that means, as the natives were carnivores with culture akin to feral cats, is up to the players.
This would be a game where the players and maybe a GM work out what's up with this Great Machine using a system either like Kingdom, Microscope, or Questlandia & Beyond, where they work out what's going on and how they need to deal with it. It maybe better GMless, so the players can have more control of what they find.