@thisfro - Yeah! That's solarpunk! 😂 Degrowth, mutual aid, decentralized and localized economies, anti-capitalism, social justice, ethical and thoughtful approach to technology, climate and ecological sustainability, etc et al. What you're describing is solarpunk.
@django @linuxgaming - You might look into taking one of the sim citites and intentionally building it car free (example: https://community.simtropolis.com/omnibus/simcity-4/tutorials/how-to-make-a-roadless-city-r89/)
You can use all mass transit forms except for busses (as building for busses would also allow for cars): https://simcity.fandom.com/wiki/Mass/_transit
Here is one discussion of someone building similar: https://www.reddit.com/r/simcity4/comments/g0cwic/my/_first/_serious/_attempt/_at/_making/_a/_city/_with/_no/
You would focus on renewable energy: (see multple variants both current to our world and future tech: https://simcity.fandom.com/wiki/List/_of/_power/_plants )
Look into various libraries and community centers and mods etc.