I’ve found that mods like iHUD, removing the cash register sound for XP, directional pipboy light, flashlights, darker nights, and storms (these can be set to be just visual rather that radiation inducing) all help make the game more immersive without dramatically changing the difficulty.

I do enjoy the health rebalancer which removes scaling health and instead makes some enemies baseline tougher and some weaker. IIRC it also makes headshots on humans instant death. No more blasting away at some scaled raider as they just keep attacking.

Recostuming the Minute Men in something closer to surplus military clothes makes them instantly less lame.

Also replacing all the pipe guns with weapon packs of real world handguns and machinepistols is for me nessesary, as I do not at all enjoy the FO4 pipegun designs.

Finally, the backyard bunkers mod allows a bomb shelter with a hatch you can place inside a settlement. Going inside moves you to a private space. NPCs won’t barge in and it’s a safe place to store extra gear.