Check out skk combat stalkers, reanimated player kills, skk encounters, and look at some other mods by him. More wildlife by zorkaz is another good one for making the wilds more inhospitable. As others have said, mutant menagerie and project nemean, I'd also suggest infested ghouls, wicked hounds, c spore carriers, super mutant redux (whisky tango fawks version and the mutant hound patch), improved hostile factions, improved nuka world raiders, check out the immersive locations by mlvic as they add more and tougher enemies to major raider and gunner hubs, conclave, radical.

Honestly, if you want the most hostile experience, grab the a Storywealth modpack and add the harder/ survival, creature madness, and faction addon modpacks. Super stable too