I’ve noticed the hill phenomena and I think it’s a mental thing, as much as technique thing. With riders that are faster than me I will pass them on a lot of hills, not all, because I have to, or I stop due to lack of speed. Steeper hills I stop and walk and they pass me. C’est la vie.
Momentum is the key, you can’t change down so you mentally can’t bail to a lower gear, just grit your teeth, clench the other end and blast up as fast as you can until your legs or lungs run out. It’s not big or clever, just the way it is. Oh, and very manly too, I tell Mrs root.
It helps to have a grippy bike so traction is not an issue.
Cycling to me is part fitness/exercise. I get more of a workout on SS with the limited time I have on a bike so it suites me.
Love my geared bikes too – fat bike good with gears but was also a blast SS.