Hi, I have couple of Cornus kousa . It is a tree , sometimes wider than taller and sometimes multi-stem. Is hard from your picture to know if your shrub is Cornus kousa but in any case I would cut the lowest branches of your plant and let it develop a leader or two. Best time to prune any tree is when it's dormant. Probably in February. They are called Chinese or Japanese dogwoods and there are many varieties but I am not an expert. I believe they prefer partial shade. 6 hrs of sun but not the hottest time.
I hope you will be able to slowly develop it to the shape you want. It will look lovely in your circle.
I gently prune mine every fall.

The RHS describes this as a shrubby or a small bushy tree depending on which page you look at.

this is the page just for the C kousa.
https://www.rhs.org.uk/plants/4391/i-cornus-kousa-i/details

Thank you. I'll be brave and lop the bottom branches off next February then. Fingers crossed 🤞