A slight curveball, but:
Heroes of Might & Magic III
It's a strategy game, but it's also an sRPG, and it's also kind of a light weight city/town builder. You have heroes who gain levels, unlock new abilities etc, these heroes then lead armies, and battles take place on a hex grid. Between battles, you have a world map to explore, find resources, fight non-player neutral creatures and armies, and these resources fuel your towns, which you can have many of (as many as exist on the map), and you upgrade those with new buildings to buff your income, recruit armies, unlock new units, unlock new spells for your heroes, etc. You can either play a continuous campaign with the same set of heroes staying with you, or (more commonly) you play a single scenario that could take anywhere from 1-5 hours to complete, after which time you will start all over again. But it's an extremely addictive loop - you're always levelling up some hero, finding new powerful artefacts to equip, building up a town, and managing resources, and it's all just so much damn fun.
I'm not exaggerating when I say it's one of the all time greatest games. And
has a bitching soundtrack. It's old now, but you can pick it up really cheap on
GOG, then install the
HD mod, and it runs like a dream on even the most modest of computers. There is a more expensive official HD remaster available from Ubisoft on tablets and Steam, but that version lacks any of the expansion packs or quality of life features added by the mods.
It may not be exactly the right ratio of town-builder complexity to other things for what you crave, but still worth a look imo.
