I’ve had the falling through the ground issue around my base for some time now and I have tried various methods to return to the relative safety of solid ground. I’ve reloaded most often, this is usually safe because the save point is so close to the moment you exited the ship but if it happens when you exit an exocraft you can lose a significant amount of progress or farming time. In these cases I try to re-enter the craft while jetpacking but often cannot manage it. If you have a terrain manipulator I have found that if I can find a low cave and while using the removal tool fly into the cave from below. This has had moderate success so far and while it shouldn’t happen at all at least I have managed to return to the solid ground most of the time.