Just an FYI that Insider Advantage is a right wing pollster similar to Trafalgar Group, American Greatness, Patriot Polling, etc. That doesn't mean their data and numbers are wrong, it's just worth pointing out.
When you compare their polling to other mainstream polls that test Harris vs. Trump, Insider Advantage is consistently off from the other mainstream polls. Most mainstream polling has shown Harris either down a one to four points, tied, or up a point or two.
As another example, they predicted on October 30th that the race between Gretchen Whitmer and Turdor Dixon for MI Governor was a tie, Whitmer won by 10. They predicted Hershel Walker was up +2 over Raphael Warnock in the Georgia Senate race and Warnock ended up winning. The predicted the Arizona Senate race was an even split in 2022 between Mark Kelly and Blake Masters. Kelly ended up winning by 4% or so. They had Dr. Oz up +2 over John Fetterman and Fetterman won by 4% or so there as well.