Both of these assertions have already been fact-checked and found to be not true:
https://www.usatoday.com/story/news/factcheck/2021/10/18/fac...
https://www.politifact.com/factchecks/2021/oct/19/facebook-p...
https://www.usatoday.com/story/news/factcheck/2021/10/18/fac...
https://www.politifact.com/factchecks/2021/oct/19/facebook-p...
They might be right about the impact, they might not, it is a complicated system that is fudged up. I doubt there is a single cause. But, if you believe the OP, that lack of trucks is big part of the problem today, then the fact checkers are most likely wrong and should update.
From their own "fact check":
"Industry experts said the rules certainly impact the availability of drivers and trucks, but acknowledged that many other issues are impacting the movement of goods through U.S. ports."
Their paragraph contradicts their own conclusion.
>Industry experts said the rules certainly impact the availability of drivers and trucks, but acknowledged that many other issues are impacting the movement of goods through U.S. ports.