Q.Pruning peonies
My peony plants have been in the ground for three years and still are very “leggy.” Can I cut back the shoots in the spring to get them to branch out and get more “bushy.” I seem to get one long stem with a flower at the end on each of my plants.

From your description, this is the natural growing pattern of Peonies.
It is a good idea to add a hoop support early in the spring to support the plants as they bud and blossom.
Here are a couple of great articles for you.
https://www.gardeningknowhow.com/ornamental/flowers/peony/peony-care.htm
https://www.gardeningknowhow.com/ornamental/flowers/peony/peony-pruning.htm