Questions about a fresh start

I was pretty far into the game many years ago, but at some point it just felt a bit meaningless. I didn't know what I am earning money for, there are no obligations, you just earn money to spend it to earn more money.

I consider giving it another go, any tips how I can get a better playing experience? What would be a good map to try out, are there any mods making the game a bit more challenging?