I think the city builder mode I have as part of the campaign in GigaMaidens will be fun in of itself, there's a population and growth management aspect to it, but you can set it to auto-build if you don't want to customize the city. However, since cities are also stages, you would be able to build the stage layout how you want and strategically place stuff that you need to defend or to give yourself an advantage when enemies attack from a direction.
I have plans for GM that will be genuinely but they're not giving your boy any money because it's not esports faggotry. Who cares.
I'm trying to adopt the mentality of "who cares as long as it's fun" over "this needs to be meticulously and carefully balanced like a diamond". Stop supporting nepobabies and support indies like me (give me your money)