So here is a question, how does the US plan on dealing with porn companies that are not in the US such as Pornhub which has it headquaters in Montreal Quebec, Canada?

How did the 40's Nazis do things? Thatms your answer

Probably the same way porn companies are dealing with states like Utah right now.

Probably by blocking access to it. Technically, your ISP could be accused of "distributing porn". VPNs may work for a while. Mostly, this part is here so they can prosecute anyone they don't like. "Porn" has no legal definition, so it's mostly an excuse to stamp on virtually anyone/thing.