Shouldn't your cadence be (ideally)constant no matter whether going uphill or flats, only changing gears to keep it that way?
I think that is a myth, and don't know anyone who can actually do it on a significant hill.
Sure, it is easy on a slight incline.
I was bicycling today on a noticeable hill, surrounded by some pretty good skinny, muscular young bikers (much better than I), and none of them was doing that.