It’s a bit cliche at this point thanks to people like Joe Rogan, but Jiu Jitsu is, imo, the best possible form of exercise. It’s not only physically exhausting, it’s also mentally very difficult. And not just because it requires deep levels of knowledge to be good, but it also resets any preconceived notions of strength. It’s not uncommon for a new white belt male that weighs 200lbs to get absolutely waxed by a 100lb…
Though don't discount other forms of martial arts, the amount of mental effort in kickboxing is still high, the coordination needed to be planning your foot work and balance out 2 or 3 moves in advance is non-trivial and that alone can take years to master!
(Also IMHO kickboxing is a more intense workout than rolling, my opinion consisting of a polar heart rate monitor strapped to my chest ;) )