Its not always easy to remain stealthy while killing with a knife, but there is just something so satisfying about the process when you are able to do it. Call me unoriginal, but I prefer the combat knife. Even with mods that make the AI smarter (such as pack attack) its pretty trivial to just snipe most of the targets from a distance (and if they try to come in close, you did set up frag mines, right?). Carry a shotgun and handgun along with a sniper. Snipers are probably the easiest, sound suppressor or not. In a game like Fallout 4, which has especially improved its shooting mechanics this time around, you’ll always want to go for the best gun. Automatics are garunteed to kill targets most of the time, but also have a higher chance of making excess noise if you are too quick to trigger.

Useful when dealing with stuff in close quarters, but not too close. An up-to-date, searchable list of Fallout 4 Weapon IDs. It will not completely eliminate the noise, but it will reduce it by a fair bit. Pistols work well, some of them anyway due to them having sound suppressors. And I don't generally try to get close to non-human creatures. Romanian Customized Assault Rifle (7.62×51 NATO (.308)/7.62x54mmR) Romanian Customized Light Machine Gun (7.62×51 NATO. Humans are easy to stealth up on, but robots are much more risky.

Fallout 4 sniper pistol