Plane floor joists, sand subfloor, or sand underlayment to handle hump in floor for cork plank flooring?
You should probably understand the root cause of the hump (settling? rest of the floor going down for some reason? built that way?).
Assuming it is dimensional lumber (not modern i-joists), I'd only consider cutting the subfloor up and planing the joists. You won't change the strength materially by lopping off a max of 5/8&quot;. You won't have to mess with a paper-thin layer anywhere (which is its own curse).
As an aside, I'm wondering why you opted for 5/8&quot; underlayment. That's thicker than typical, and will make a bit more of a step if everything else is based on the subfloor. Typical underlayment is more like 1/4&quot;.