I think a fun sort of idea to play are world scenarios. these affect the world you play on itself over the character.
example. The flooded world. The main level of the game is all deep water tho only on outside blocks. buildings that you can enter from are fine mostly some like missile silos or farms are going to be flooded but office towers or other stronger buildings are going to be fine. also i would say they would change a few thing like more taller buildings spawn in that worlds and buildings have roof access. note if the building has glass walls like the first floor of the office building it’s going to have a flooded first floor. know most zombie and other monster will be dead but this is more harsh world survival over lots of enemies survival and fish monster are a thing they they may happen. also boats would be needed and diving gear.
solar end. The sun starts emitting extreme level of UV radiation making it impossible to live outside without protection but night is safe. this is more a timed survival since you cant go outside without heavy protection. i would add tho that solar panels get a super charge in this world so they are risky to use but very effective.