Going to Utah NP's.

My hiking kit right now is an X-T4, 10-24, 70-300, and the 50/2.  I used to bring the 16-55 as well, but I've been experimenting with allowing the 50 to cover the gap between 24 and 70. The 50 is great for stuff like isolating flowers and such.  If I was going someplace where I wasn't expecting to do a ton of wildlife spotting(like Utah), and so didn't necessarily need the 300 reach I'd bring my 50-140 with the 1.4tx instead of the 70-300, and leave the 50 behind.  But that's a bulkier, heavier option than the 70-300 in addition to to lesser reach.

If my goal was to balance minimal gear and minimum fuss, I'd probably see if I could get away with bringing both the X H2 and the X-t4.  I'd mount the 10-24 on one and the 50-140(or 70-300) on the other.  Sure, it's more gear, but it also means not having to stop and change lenses, and since your wife isn't carrying the gear (I assume :-)), maybe the extra gear wouldn't bother her as long it meant you could could photograph more efficiently.  Just get some Peak Design type camera clips to attach the cameras to your pack straps/belt for quick access.

But if I could only bring one lens/camera, I think it would have to be a standard zoom like the 18-55.  I've been to Utah and those parks 3 times, and I didn't own an ultra wide, just two lenses that covered the 24-300(FF equivalent) range (Olympus 12-40 and the 40-150) and I don't remember being unhappy. But I don't think I'm a UW guy for landscapes. And I would have definitely missed the ability to compress some of those wide open landscapes without a 300mm FF equivalent.