I responded to your other post. OK to remove lower branching as you wish and necessary if in fact coming from below the graft (photos not providing enough detail to confirm).

"Should I take off about a third of its height when dormant and start over? If I can’t get it looking better I may take it out next spring"

Not sure I understand your thought process here :-)) Why would you want to do that? Or maybe better approached as why do you think that would improve the appearance? Most JM's do not develop a very precisely uniform growth habit or appearance and often develop an uneven canopy structure. A planting area that offers light in a very directed manner (like your oak underplanting area) will also encourage uneven growth. That is just part of their charm. With the exception of a few wayward lower branches that can be removed without altering the overall appearance of the tree, I would just leave it to grow as it wishes.

If you ask me it is just beginning to show it's personality and I would leave it alone.

Hard to tell from a 2D image, but it's certain you have a lot going on where those 3 branches (or the main trunk and 2 branches) all occur within a matter of a few inches. I'd remove one of them - probably the middle one, + any other small branches that occur in very near proximity to that near trifurcation.

Al