Fork length can counteract or exaggerate head angle (steep climbs well, reacts fat (road, DJ, BMX) and descends nervously on the rough). Likewise seatpost layback or not plus saddle position and height adjusts your position above the BB shell and proximity to the rear wheel contact patch. Again the chainstay length then adjusts the weight distribution.
Flickable (DJ):
Short wheelbase, low weight, frame size biased to smaller, 26″ wheels, hardtail.
Confident descending (DH):
Slack, long travel, full suspension, slack seat tube, low top tube, short stem & wide bars, big tyres.
Climbs well (XC):
Steep head angle, steep seat tube angle, short travel/rigid, longer stem, hardtail, lightweight, skinnier lighter tyres.
I’d stick a shorter stem and longer travel fork on your hardtail. FS bikes just don’t climb as well, saving some weight on it will make it a little more flickable and climb better. Suspension settings have a huuuuge impact too, this may ‘upgrade’ the Zesty.