The closest I've found for a room builder is this
https://planner.roomsketcher.com/
As for city planning though I'm not entirely sure. I remember seeing this thing shared on Twitter called Twinmotion that's built through unreal engine but it's not something I've had the opportunity to use or experiment with yet
Link's here:
In some cases I've taken to using Minecraft if I've got something specific in mind and I'm willing to put the time in to building but I haven't really found many other alternatives.