Tour Int says the two bikes ride about the same on paper in the test size.
The Cannondale has a round seatpost, which would make it easier to mount bikepacking bags vs the canyon double spring post. The Cannondale looks to have about 5mm more ground clearance if you’re going over rocks.
The canyon is a lost (30mm) longer in front than either bike for toe clearance with fat tires. It’s also 10mm lower front if you want to slam that stem. It has nicer wheels, crank, tires, a lot better tire clearance, and bag mounts. Given the longer front, it’s probably better to take a surprise rock/root/pothole hit with, but would be harder to ride up steep, tight single track hills.
The 700 v 650 shouldn’t make a difference climbing aside from what tires you’re running the the diameter of the wheel/tire combo. 650b is just a wheel that’s 20mm lower than a 700c. If you’re running the same “40c” tires, the difference is about a 6% lower gear (roughly a half or one full cog in back)