There sure as shit should be a fully automated and publicly available diff system for all legislation, Federal and State. Ideally in a normalized format, but that's probably a pipe dream
Connecticut does a somewhat job when they publish the HTML text of the bills, but this is only after they are signed and become park of the statutes
As an example https://www.cga.ct.gov/current...: All the Public Acts that were proposed and then signed into law amending this statute are in the tan color, some background history and the changes made are in purple, citations in case law and other statutes are in red.
It's better than nothing but it's not hyperlinked or graphed or anything fancy to actually understand how each thing relates to the rest.