5 to 10? I can tell you are still a Johnny Newcome to game design lol. I'd say 2-3 things would be plenty. Overdesign means confused players, harder to implement and more bugs, none of us benefit from that.
We're generally thinking everyone spawns in the pine forest and it is normal difficulty. Snow will be colder and have slower moving harder to kill zeds, and cold will make you shiver which burns through calories faster, so take lots of food and cold weather gear. Desert will make you hot so all the sweating will require a ton of water to drink, so bring a lot of water. Wasteland will be radiated, so bring hazmat and rad pills. Burnt smoke will lower stamina, so maybe bring coffee or stimulants. All non pine forest biomes would have increased game stage, so harder zombies and better loot. Radiated zone would be highest game stage modification.