I’ve helped with a few other zoning visualization projects recently, similar workflow. The only similarity is that each city/jurisdiction makes its data available in a different way. It’s usually accessible but it does mean there’s a lot of work munging the data to a usable format.
Here’s one of the projects: https://github.com/kfarr/zoningviz
The other thing I learned is that some of the data sets use a destructive insert, so unless someone is doing a data snapshot data elements can be lost. (The vendors charge extra time-series option.)