You say a challenge from an employee will take you multiples of X hours? Then practice it. Keep working at things that are hard and eventually they will come together and get easier.
If they say something should take X hours or less though, and I'd take at least double that, it worries me. Maybe the job is just beyond my skill level right now, I'm not sure.
I currently have an ops guy trying to transition to development and he is seriously 10x on the 4 tasks I've given him recently and I will not use his work in production even after that work. He does the meetup thing and can talk the talk but I've had to completely write 3 of the 4 items myself and the 4th sits in the back of my mind. Only reason he still works for me is its hard to fill this specific ops role and he does that ok though I'm questioning that now as well. If you are 10x slower then yes please stop now.
Don't let that discourage you as you don't sound that far off the mark and maybe it will click but it does sound like you are probably at a disadvantage technically. If you get the opportunity focus on something else that differentiates you from the rest like documentation practices.