I would say they can be relatively easy from cuttings, I’ve gotten 100% success rate before, planting cuttings in spring without any root hormones and keeping them watered. I’ve had failure too if not paying enough attention or just some years are not as conductive to starting cuttings.
I have a larger problem keeping them alive in their future. This is another plant I have started to plant on south sides of hills as my stand of them was on a northside of a hill, and they all suffered dieback. Maybe winter dieback if cultivars aren’t as hardy or canker problems. Oddly enough haven’t had much luck with autumn olives.