Echoing what a lot of folks have said, it is a combo of bike geometery and fitness (I guess unsurprising, since there isn’t really a whole lot else to change!) When I got a long-travel bike my climbing suffered too…but, I didn’t care because when rolling a long travel rig, the whole point is to go fast downhill, not up. I think if climbing is more your gig, you may want to try something way lighter, less slack, and with less travel. I think there is a real unfortunate snubbing of shorter-travel bikes in some places, I think it is even subconscious sometimes. We are trained to think that being a boss means slaying it on a long travel bike….but the vast majority of riders never get to the point where they will take advantage of the new aggressive trail bikes, and just end up with something that feels sluggish. It is a real shame imo. Maybe this comment doesn’t apply to you, if not, then apologies! It is just something I have noticed…loads of newer riders getting slack 160 rides that they wont be able to take advantage of for years (if ever) and suffering on the chill xc trails and long climbs that they end up riding.