If you want a less harsh ride...
You do NOT want Fox or Bilstein or Rancho 7000 (to name a few)
You want Skyjacker Bkack max or Rancho 5000x.
We install both here for customers with good feedback.
Back to your power.
Sonething is off here. Your description...or your Jeep.
My son has (I've owned a few myself with 31's) a 4 cylinder with 32's. He is running stock 4.10 gears. I razz him about that hot rod he's driving but even still he has no trouble hitting 77mph in it.
That said, if he hits a wheel chair ramp let alone a real hill without down shifting, it will drop 20 mph.
In other words the little 4 that could...can't...overcome much adversity like even slight hills without downshifting and or dropping 20mph before getting back to 70 plus 1 mile later.
I'd say from your description of barely making it to 65mph...having 33's but with 5.13 gears...
65 should be no issue whatsoever.
Echoing again my son can hit 77 mph with 32's and 4.10 gears.
You've one inch bigger tire and have more weight but you also have a full ratio lower gearing(Numerically higher)
Something is off here....