My favorite survival game ever is Unreal World. It’s definitely not for everybody, as it’s nearly 30 years old and it can be clunky, but it still gets regular updates and new features. It takes place in a fictional Finland-based land in the iron age, and it’s brutally realistic. You have to manage everything, not just hunger and thirst but sleep, fatigue, wounds, even nutrition. Death is permanent and easier to come by than avoid. You can get the latest version for about $10 on steam or the previous version for free at http://www.unrealworld.fi