Workflow for Yakuza games like environment

I was wondering with games like Yakuza, Sleeping Dogs, GTA, Cyberpunk 2077, etc… Something like this: https://www.youtube.com/watch?v=mWaC_VSncEg&t=220s . What is good workflow for asset creation and world building? Recently finishing Yakuza 6, I’ve been thinking about how to go to recreate that kind of environment (On much smaller scale though). Their environment feels way more organic than anything I try to come up with using modular approach. There are many places in map which are unique to just that one place, it doesn’t reappear anywhere else. Roads/walkways are not just flat, they have parts where they elevate, again pretty specific for just certain parts of map. Walkways don’t curve same around every corner. Anything to point in right direction would help, thanks!