I don't think it's your inexperience. I have found most people don't care if you know something else well that's outside the remit of your current role. Some are actively threatened by it.

I also switched careers 10 years ago. I have found that having this broad experience has helped me to make better decisions, understand different points of view and to work with others better.

But I usually have no ability to directly apply the experience from my first career, and very few organisations would ever want or allow me to. It's a pleasure when I can, but it's rare.