Forgot to add pics

A few things I'd like to mention that you did not ask.

Plum trees throwing out long branches 4-6 ft are common. Your tree was planted way too close to the house. Fruit trees need a lot of sun to produce well and reduce diseases.

My suggestion is early next spring, dig it up and plant it at least 8-10 ft from a house in full sun if possible.

I would move it this coming winter, when it's dormant. But you can still prune it now. I would prune it to about head high, which will encourage lateral branching.

Thanks for the replies.

It's a side yard. There's not a lot of space. The view is to the south so it gets about 6 hours of midday sun. I know it's not ideal. On the other side of the fence, just out of view to the right is my neighbor's fig tree which is huge.