Try explaining to them why you have a degree in Electrical Engineering but work as a Data Scientist. My friend tried, and it would be funny if it didn't almost cost him his job. He literally got in due to a shred of mercy caused by his girlfriend's tears at the possibility of a refused visa.
The USA sometimes feels like a dystopian nightmare, mainly populated with idiotic yes-men and ruled by Machiavellian bureaucrats. There are a few niche ecosystems that are impressive, but they are by far the minority.
You can theoretically only do the border visa part once.
Also remember to have the documentation when you cross the border, in case some border guard forgot to stamp your passport with your renewal number, which has happened to me.
Their computer systems are so bad (or they are so untrained) that they can't just look it up by passport number. It's supposedly a pretty complicated process on their end at the secondary screening office.
For the TN program you simply present yourself to the immigration officer when you enter the country (this part is something that even a citizen will have to do), show them your documentation, pay $50, and you're done. You don't even have to fill out a form.