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Survival and base-building Mechanics
(ttrpg.network)
A place where Game Masters, Dungeon Masters, Storytellers, Narrators, Referees (and etc) can gather and ask questions. Uncertain of where to take the story? Want to spice up your big baddie? Encounters? That player? Ask away!
And if you have questions about becoming a Game Master you are most welcome with those as well!
Rules
The most direct resource for you that I can think of is Mat Colville's Strongholds and Followers. Haven't looked at it but I am aware of it. Also look at DMs Guild to see 8f someone has made anything, there are gems in that program.
Beyond that all I can think of lies outside of DnD. Dungeon World (or hacks Homebrew World, Stonetop) does community needs and wants in a more abstract way. Might be an inspiration depending on how detailed you want to do it. If some (abstract) trackers are enough go for it. Speaking of trackers Ironsworn has the best implementation. My opinion of course.
Kevin Crawford's X without Numbers systems (World for fantasy) has their faction turn you possibly could get inspired by. It is a subsystem for the GM to play out conflicts between factions to drive the background narrative forward.
There isa Forged in the Dark game called Wicked Ones which heavily features basebuilding. In short you play as the monsters building their dungeon to "farm" adventurers. Think Dungeon Keeper. Think most FitD systems feature basebuilding in some form.