Fallout 4

You don't need to.
1) Obtain lots of weapons by purchase or looting. Ones with lots of words in the name (i.e. produce more components) are better.
2) Go to settlement.
3) Toss all weapons on the ground.
4) Enter workshop mode and scrap all the weapons.

I have towns that have 5 story buildings with an empty meter from doing this.

If you have the manufacturing add on, you can also just shit out a bunch of basic weapons to trash, as well. This works on the console. Fuck my OCD and my compulsive need to build up every shithole town, as I have fully functioning maxed settlements everywhere on my current playthrough. But the upside is that I have basically unlimited caps from by extensive bar and medical franchises.

But yeah Far Harbor has been an amazing add on, pretty much everything the base game should have been in terms of faction choices and story. The robot add on is fun, but completely trivializes everything if you actually build robots for combat companions and for your towns. Other stuff is great if you are into the building, meh if not. Best part about the add ons is concrete, circuitry, and steel becoming a lot easier to obtain.

Everything is tedium at some level, if you want to get all pussyhurt about it. Plus you want the parts from the guns, anyhow, so all you are really adding is the part where you drop shit on the ground to grind it up, which you already have to do if you are unable to build weapon crafting stations in each town.

More practically, though, the size cap is only an issue in a few towns, anyhow. Most of the available build places have enough basic build room to let you crank out 20+ person communities with ludicrous defense and furnishings, unless you are building a giant flying battlestar galactica or something (I actually did this) with the build mechanics. But in that case, you already are engaging in a lot of tedius stuff. The main places with capped build that I have found were Sanctuary Hills, Starlight Drive In, and Hangmans Alley. The last one is cramped anyhow, so I understand it somewhat, but the first two are the primary build spots for a lot of people (along with Abernathy and Sunshine) so it is indeed stupid that they did that.

Have not dug into the Vault Tech side quest yet (still chewing up Far Harbor), but the best addition so far is the settle management console they added. Having to build things in silly ways to more easily assign junk collectors and farmers was a huge pain in the ass.

Well, Far Harbor helped a little on that front with weapons. The issue of ballistic upgrading stuff remains, however.

Anyhow, building my spaceship over OCD Island with the new Vault components. I need a source of mass rubber. Vendor mining with my 100k caps is slow as shit.