Check out 'Against the Storm' my friend!
He likes building games that use an isometric view and simple grid so I figured Against the Storm is a nice modern option although I can see why one would dislike it because of the roguelike elements.
> I mean is not even a city builder...?
What defines a city builder? Steam describes it as one. Game description: A dark fantasy city builder where you must rebuild civilization in the face of apocalyptic rains...
I'd consider a city builder to actually... Build a city.
Against the storm is more of a strategy game, with caveat that your strategy needs to center around the pure chance RNG for what building you're allowed to unlock.