I'd love to see something with the flexibility and sandbox nature of Skylines and the historic themes of the Anno series (which has pretty graphics but is ultimately tied to a grid and more about sticking buildings on the right tiles to maximise efficiency than worldbuilding)
Have you tried 1800? The grid there is a pretty "soft" one, meaning it's more like a visual guide than anything enforcing gameplay. It's not that different from zoning and road-building in Skylines, where your beneficial buildings (like hospitals and police stations and schools) also have a limited radius of effectiveness.
The campaign might be linear, but the sandbox mode feels like a mix of Cities and Civilization to me. It kinda scratches that sandbox itch, though the focus on trade (vs city-building) got a bit tiresome for me.
I think CS:2 also copied some of the mechanics from 1800 (like the customizable placement of farms around production buildings), trade buildings for lumber, ore, etc.
