Design suggestion. Trees are structured by repetitive fractal geometry. Patterns are repeated with slight variations. Look at the zelkova, which branches are not like the others? Some branches go down, then out, then up. Some branches leave the trunk rising up, then out, then down. The two styles of branches don't go together. The tree is confused looking. In all seriousness, I would consider cutting off every single branch. From bottom to top. This will leave a long trunk, but it does have some taper. You could shorten the trunk line if you like, but you don't have too. Zelkova are pretty good about back budding, give it two years after reducing to a single trunk, and see if branches pop where you need them.
Alternate on the above theme, convert this to a conventional broom. Remove all the branches, then shorten the trunk to the point you want your broom to start at. You have a ''nice enough trunk, and a better nebari'' now its time to do something about the rest of the tree. Your branches are a mixed up mess, none of them really belong with each other. Best to start the branches over.
Another benefit of starting branches over. In general, branches should be less than half the diameter of the main trunk. Your branches are getting rather thick. When branches and trunk are too similar in size, they tend to create a ''shrub'' image instead of a ''tree'' image.
