After you survive each ghost for the first time, there aren't a lot of rewards geared toward later-game achievements/progression. (Yes I know about the prestige system and while it's cool it isn't what I mean here.) Even the more grindy options like "Get 100 spirit box responses" or something would be nicer than nothing. Maybe something that tracks the number of times you got the special Banshee scream, or accidentally got killed by a Deo, or lost X sanity over the course of your career, etc. Or honestly even something akin to what they have for maps like the camps or Point Hope, to reward players for playing on different maps more. I like having goals to work toward in games, to watch those tasks get progress and checked off.
This is also one of the few games I enjoy playing with friends more than playing solo (not public lobbies bc that's just... painful...). It would be really cool to have an alternate version of the Apocalypse challenges that reward you for playing cooperatively. Could ofc keep the current requirements for solo play, but allow a co-op version for unlocking it as well, perhaps by forcing a higher multiplier based on the number of players, or doing it multiple times if playing with others.