[Fanatical] Frostpunk: Game of the Year edition ($7.47 / 89% off)

It’s more a game of building a small civilization while dealing with extenuating circumstances, like increasing cold weather, a lack of resources, a combative populace, and random things like extra survivors that appear, etc. Well worth the money if you enjoy those sorts things of games.

I don't have great insight into the game but it's more of a city builder (Banished, Surviving Mars, etc.) than a system builder (Factorio, Satisfactory, etc.)

You're more likely to put children to work than design a main bus.

Much less complex than those. Iirc there's a difficulty slider or options as well.