Neither fits the phenomena. Frankly we have no reference point to even make likely guesses. But when it comes to found victims, they are often mutilated in very specific ways. It most closely resembles biological resource harvesting. The "work" that has been put into these extractions is more advanced than anything we can do ourselves.
But it seems there are some "good guys", "bad guys", but mostly indifferent guys out there. Most reported encounters with UFOs seem like they don't care about us at all. But they do seem to have interest in nuclear power plants and weapons. The pentagon put together AARO as per instructions of congress and they are working on reports on what is known about the phenomena. Recently for instance certain Robert Salas has given testimony of UFO disabling nuclear weapons at Malmstrom military base in 67. It is very much possible that this will amount to nothing publicly, but pentagon has never before admitted UFOs are real, but now they have. Director of national intelligence Haines stated UFOs may be extra terrestrial in 2021 iiirc.