Think I need to do a few test rides to put my mind to rest!
I rode a 27.5 evil insurgent about 5000 miles, then last year bought a ripley ls, a yeti 5.5, and a yt capra, all 29ers. I’ve now put about the same amount of mileage on those three collectively as I did on the evil. In three consecutive runs on a 15 mile downhill, during which I went full gas, the evil was the slowest, then the ripley, and the yeti was the fastest. However, all three were less than 30 seconds apart, so it was surprisingly close for such a long segment. So in terms of time, I don’t think you’re going to be giving up as much as you might think. The way you feel on any given day is probably a much bigger variable than your wheel size. The evil, now sold, was the most fun bike of the four but I’ve come to love the others as well. Good luck on your next purchase!