What I enjoy most about survival games is the artificial sense of accomplishment. Going from nothing to mastering the world around you is a great feeling that is sadly somewhat lacking in real life most of the time.
The games I've loved the most have had "progression" trees with many, many steps. No single step should require incredibly long amounts of grinding to accomplish, but strung together they should be a steady drip feed to keep an accomplishment-reward cycle going for as many game hours as possible.
I've enjoyed many different survival-ish style games in many different settings and formats, but that feedback/reward-loop is the one common element I'd say that they all share.
Another thing that really keep me engaged with any game is having something else in the game world that makes it feel worth living in/for. In many games, that might just be some NPCs that make the world feel "lived in". I haven't played Star Shelter yet (it's on my list!), but maybe there could be a pseudo-sentient AI/robot that gives new and unique dialog as you accomplish each part of the progression tree? Maybe an AI wired into different hab areas, and as you enter each one it will broadcast stuff to you...? Just something to help you feel connected to the game world.