I also have 16gb of ram and I can play Minecraft modpacks with shaders and like 700 mods with no issue, I also play project zomboid with about 400-500 mods and no issue, it just seems this game is terribly optimized for ram usage. I've tweaked all setting I can find and nothing stops it from sitting at 13gb of usage even just sitting on the main menu. I only have about 40 mods installed and most of them are small things like being able to stack more things on the ground.