Why would my gas pedal and passenger floor board pulsate when going ONLY 60-65mp

What is your question?

I have gone to 6 shops or said the tired needed to be rotated and balance. After each time of that being done the problem still occurs. One shop said it sounds like a transmission problem, one shop said the right passenger axel is bent. 5 out of the 6 shops said the axel was fine and none mentioned a transmission problem besides one. I bought the car used, with 2,000 miles on it. Rims are not bent. Once out of the 60-65 mph range the pulsation goes away, and it occurs when my foot is on it and if i left go of the pedal.

What makes this problem better or worse?

When going 60-65 mph

How long has your 2021 Nissan Maxima had this problem?

1 years