Oh, so if it's not meant to be an horror game and more of a dark adventure game, then an humble suggestion is to add some friendly/neutral NPCs. Like in the first Dark Souls you have a friendly NPC helping you early on, even if they get killed soon after you soon start finding new friendly/neutral NPCs right after you exit the tutorial area. Similarly last of us has the whole duo protagonist mechanic, they provide emotional support for each other. Horror games usually have solo protagonist because being alone is pretty scary for most humans, and Bio-Synthetica thus feels like that because you start on your own in a seemingly empty world with only automatic machines and message logs, then the first other characters that do talk are pretty clearly up to no good.
IMHO something simple would be that instead of the first room's machines being automatic devices, having them be operated by friendly NPCs that you can chat with a bit, maybe find some human survivors or other scattered robots/AIs that give some feeling of companionship, maybe even some shady merchant willing to trade crafting materials/upgrades. They could also provide the tutorial advice instead of a non-participating narrator. But if the protagonist is all alone in the world against hordes of monsters, then that's gonna feel more towards horror.