Both liberal and conservative outlets are reporting on his "real estate loophole" taxes.

There were lots of tax benefits or loopholes right before the tax reform act of 1986, which is what helped start the big recession that lasted into the 90s.

Applying for residency and moving to Canada isn't an option even temporarily.Are there any loopholes or other tricks people have successfully executed to reduce or completely avoid this tax LEGALLY?

I sure hope he either found a good lawyer to make a loophole or isn't breaking the law.

Any loopholes?

There isn't a loophole without a penalty.

Look up STR tax loophole 

https://www.foxla.com/news/couple-buys-riverside-dream-home-but-seller-refuses-to-move-out-in-eviction-moratorium-loophole

What can I do to make sure there aren’t any loopholes he can use to get out of paying me?

Great points from Linda, with one note on the placed in service date if you are interested in using the short term rental “tax loophole”.I’ve seen many people confused on this but the “Placed In Service” date works differently for long-term rentals and short term rentals.