You the PC have prewar tech and experience with it fresh in your mind. If you can repair Mr. Handy bots to where they can help you salvage, loot, capture, repair and fabricate or craft tools to fabricate parts for other bots, fabricate or craft up grades for other bots. Handys are after all handyman bots designed to repair and maintain building and probably appliances and according to wikis each other.
With Handys in particular you can probably make failed vaults livable and redoubts for nearby settlements so everybody does not have to killed or enslaved by invaders before help can arrive, and nearby settlements have a stake in their survival.
You can help settlements willing to accept the help repair equipment that makes civilized life easier. You can help them make or restore spinning wheels, looms and sewing machines to make new clothes out of natural fibers like hemp or animal hair like wool. You can help them restore pumps, generators, machine tools and power tools, a manufacture small arms ammo. Help with irrigation wells, growing crops and fibers and maybe producing and containerizing methane gas.
It shouldn't be hard to build brick, mortar, cement or sawmill capabilities, for that matter to build new buildings out of wood, and/or cemented stones from a creek or stream bed. Bots or people can chip 200+ year old deteriorating mortar from salvageable bricks so they can be reused with fresh mortar.
Settlements could be strong stone and mortar, or brick and mortar bunker like buildings that will survive all but the heaviest weapons fire, and arranged so they provide good fields of fire to kill raiders attacking different buildings without worry of harming those inside the buildings they are shooting raiders out side of. No place to take cover from one building without being exposed to shooters in other buildings, and maybe improvised claymore mines as well as turrets.
Such settlements could require residents to keep things clean enough not to attract disease carrying vermin or give enemies places to hide or take cover behind trash and rubble for safety and security reasons. There can still be rubble and ruins in the background to remind people of the war.