"A polygraph test arranged and reported by a highly friendly party (your own PR firm) is useless."

So you go on a podcast and another guest who is friendly with the host says "Hey, I know a guy" who does polygraphs...
Yeah, that's much better.
The next time anyone is asked to take a polygraph as a condition for a job or security clearance, say, "Wait a minute, you're friendly with that company, I want to pick who I take a polygraph with," See how that works for you.

Again, nothing is going to satisfy those who want to believe she is guilty. You can keep piling on conditions until the whole thing is truly meaningless.

In her shoes, the only way I would submit to another test would be if all the shady actors involved (including garrett) agreed to take the same test and I could submit some of the questions for them. "Garrett, have you EVER colluded with another player in a poker game? Have you EVER seen another player's cards and benefitted from the information?"