I don't think FTL drives were ever going to be in KSP2. Interstellar travel was going to be via torchships. You can argue _those_ are unrealistic, but they're at least feasible without needing to break the fundamental laws of the universe.
I thought it was warp drives, and possibly stargates. (See the arches with the carvings on Mun). Regardless, we're talking travel time in hundreds of years. Even with time warp, that's pretty boring.
I don't think there was anything official about warp drives or stargates. Supposedly they're planning on having a fast enough time warp even for hundreds-of-years journeys — assuming they ever get that far.
