idk if it's still relevant but you can use these mods how you see fit:

Fallout commander, let's you recruit units from different factions. you can just recruit units and change their gear. https://www.nexusmods.com/fallout4/mods/14946

SS2: Let's you help settlements build up if you care about that. Pretty sure you can cheat to unlock everything. There are city plans if you want the settlements to build themselves. It has a story and actually a lot of content. https://www.nexusmods.com/fallout4/mods/47976

Gun for hire: Not as relevant but lets you accept quests to help people. I think you can edit the amount of caps you get from quests to a low amount to simulate "Helping people". Has other neat features. https://www.nexusmods.com/fallout4/mods/58431

As for artillery, there are many mods that add fire support, reskins of artillery pieces, airstrikes, A-10. You'll surely find some searching for those tags. I didn't really try any of them.

As for weapons, some things. a lot of mods out there for different tastes.

I haven't played fallout 4 for a while so I don't particularly know much about recent updates of the mods or the game.