Which CS departments worldwide provide the best undergrad education?

It is possible to find data on CS major average salary by school. For whatever measure of CS graduate quality you use, much of the difference across schools is probably due to differences in selectivity rather than teaching quality. I live in Massachusetts, and I am confident that MIT CS graduates are on average better than CS graduates of UMass Amherst (the state flagship university), who are on average better than CS grads of UMass Dartmouth (a less selective state university). That does not mean the teaching is better -- and probably what is taught should differ based on the average ability of students.

I think a great undergrad student would do just as well at any top-tier research institution. I would bias towards schools near Boston, NYC and SF/Palo Alto for the industry connections and opportunities. Maybe MI/PA for Auto/robotics.

All top-tier institutions have the faculty and opportunities to support undergrads as much as necessary. Extremely successful undergrads, are such because of what they do outside/beyond the classroom not because of the core coursework. If you continue beyond undergrad, pick a school that aligns with your research interest or has the industry network that you need.

can I answer none of the above? I went to https://www.cs.pitt.edu/ which is down the street from https://www.cs.cmu.edu/ but everything I learned about problem solving, code quality, "fundamental concepts" I learned after I graduated at real jobs.

And some of the best problem solver and code quality engineers I've worked with over the years either didn't have college degrees or majored in another subject.