that particular hipster frustration of "MODPACK (RPG)" nearly always translating to racist classist D&D sorry I mean your character capabilities are defined by race, class, and level progression, as in Dungeons and Dragons.
eh whatever it's what people know. I just don't feel the urge to play them.
How about a sandbox RPG for your sandbox computer game? How about some GURPS? Wait that sounds more like a Vintage Story fit.