Looking for city building game

[Riftwolf]

To elaborate...

I had the idea of using a hex grid for map building in a tactical game where players have to take down a much larger enemy with good tactics rather than brute force. Stuff like cutting supply lines to isolate important resource sites, carefully choosing targets, avoiding reinforcements, etc. To generate the maps, I started trying to put together procedural rules for how a city could develop and gaining optimum productivity in a restricted area.
Then I thought 'probably someone smarter than me's already done this'. The only one I could think of was maybe Civ, but running Freeciv on my phone is a great way to cook an egg. If there's a free/cheap alternative anyone can recommend (even if it's a set of procedural rules I could use to manually build the map with counters as my original plan was) I'm open to suggestions.l

[Cespenar]

To elaborate...

I had the idea of using a hex grid for map building in a tactical game where players have to take down a much larger enemy with good tactics rather than brute force. Stuff like cutting supply lines to isolate important resource sites, carefully choosing targets, avoiding reinforcements, etc. To generate the maps, I started trying to put together procedural rules for how a city could develop and gaining optimum productivity in a restricted area.
Then I thought 'probably someone smarter than me's already done this'. The only one I could think of was maybe Civ, but running Freeciv on my phone is a great way to cook an egg. If there's a free/cheap alternative anyone can recommend (even if it's a set of procedural rules I could use to manually build the map with counters as my original plan was) I'm open to suggestions.l

Even Civ is pretty boardgamey in its city growth mechanics. I'd suggest just designing stuff on your own, which is 90% of the fun in such endeavors anyway.

[Wookieetank]

There's Dorfromantic, a hex tile placing game on Steam (and likely elsewhere). Think Carcassonne, but as a chill single player game. Also has a creative mode option for just making pretty maps. Usually runs $14, currently on sale for $10. Don't get a whole lot of variety in tile types though: city, river, train, woods, farm, and open field.

[Cespenar]

Not to be that guy (definite that guy vibes), but Dorfromantik also falls heavily towards the boardgamey side of things, whereas if I'm not mistaken, the OP asks for a simlike enough system to not invent the wheel again.

[Javonte]

Games like Unity of Command or BattleTech could be great fits. If you prefer manual map creation, tools like Hexographer or tabletop RPG map generators might be useful.

[BloodSquirrel]

To elaborate...

I had the idea of using a hex grid for map building in a tactical game where players have to take down a much larger enemy with good tactics rather than brute force. Stuff like cutting supply lines to isolate important resource sites, carefully choosing targets, avoiding reinforcements, etc. To generate the maps, I started trying to put together procedural rules for how a city could develop and gaining optimum productivity in a restricted area.
Then I thought 'probably someone smarter than me's already done this'. The only one I could think of was maybe Civ, but running Freeciv on my phone is a great way to cook an egg. If there's a free/cheap alternative anyone can recommend (even if it's a set of procedural rules I could use to manually build the map with counters as my original plan was) I'm open to suggestions.l

The big problem with that, from what I've seen, is that Civ-type games have such difficulty designing AI that can properly play according to the complex ruleset that they wind up have to let it cheat, and that tends to make it difficult to have that style of strategy. I've played a lot of grand strategy games, and I've never played one that did the kind of strategy (or, as it's called military theory, operational warefare) well.

[GloatingSwine]

For a game like this I think the enemy needs to act highly programatically and explicitly not by the same rules, making it almost more of a puzzle game than a strategy game.

I can think of a few where there's an overwhelming enemy, but the only one that's close-ish to a city builder is They Are Billions and it's really more of an RTS base builder. City builders with pressure tend to be survival pressure against hostile circumstances rather than an enemy (Ixion, Frostpunk, Against the Storm)

Creeper World has you build stuff, but it's just a tower defence rather than a city builder.