I've measured internal bluetooth input lag with an Xbox one S gamedpad on both Rpi 3 and 3+*.
I did not notice any difference.
With 100 ping, mean is around 16ms with a min of 14min and a max of 27 in both case.
On the other hand I noticed a difference when I change the driver.
By moving from xpad to xpadneo, input lag goes from a mean of 16ms to a mean of 22ms (min of 19ms and max of 48ms, from 100 ping).
So I guess the difference observed by choum is due to software and not hardware. Have you tried this on a fresh install ?
*The tests were carried out with l2ping command on a blank installation of raspbian lite (last version: 2018-11-13), after a sudo apt-get update upgrade.