I think I am really good at explaining things. I don't think anybody ever listens to the explanations.
But in this case, the explanation is this:
Installing lifts is not a profession, nor it is a trade. The OP says he'd like to have a professional but that's the wrong word. Nobody is a professional lift installer. It's millwright work, and millwrights don't do it. They have better things to do. So the "skill" simply isn't available at any price. You can get experience, but not much of it. There aren't enough lifts in the world to generate much of a body of experienced installers. There are a few of them somewhere, I'm sure. You can get "labor" everywhere. There is an ocean of it. But really there's not much labor to putting in a lift. There's a little bit.
In a case like this, you could have a training program that gets people really good at it. Manufacturers could sponsor such a thing. That is not where we are.