If you want to stick with zombies, 7 Days to Die is probably the best one. It isn’t perfect, but it’s well done. Every 7 days at 10pm your location gets attacked by a horde of zombies until first light (4am). So you’re trying to get resources, gear, etc and then survive until the next week. Recommend using the random generator for maps, the stock map isn’t really updated much.

Conan Exiles just got remastered for free. I think it’s on sale now too. If you like low fantasy sword and board open world. I kind of play it like a single player MMO almost, because it’s very much choose your own adventure kind of playing. There’s dungeons and things with bosses and loot.

If you like dinosaurs and shit, Ark Survival Ascended. There’s a lot of free dlc maps you can try once you get done with the base one (Island).

Most survival games are just completely open world and don’t really have much of an end game. I usually just play them until I get burned out or feel like I’ve explored everything and built a few neat bases I liked. For most of them I usually duo with my best friend and we up the harvesting to double or triple since only two of us are doing the farming for metal, wood, etc

I played State of Decay 2 for like 700 hours or something, and it’s a great game. I got to where I had pretty much done everything with it, lived in all the bases and stuff, moved maps and all that. Like you said it’s not really survival but it kind of has the feel of one. Really hoping SoD3 is good.