The view in your third photo is the most interesting of the three for me. Yet, I see some upper branches that appear to be thick/heavy. I am sure you will want to remove those and start growing some lighter branches in their place. I also see a lone branch that zips up and to the left. It is discordantly straight and uniform in thickness. You will at least want to shorten it markedly so the subsequent new growth will produce a branch with more movement. In the end, it may prove to be better to eliminate it altogether, but in the meantime (this year and maybe next), it will contribute to further thickening of the lower trunk (i.e., its always good to hedge your bets).
Meanwhile, I suggest you focus on the nebari and root development, which means bare rooting and replanting it in your chosen bonsai medium in the next few weeks (be sure the tree is securely anchored to the pot). Then study bonsai design principles and images of Japanese maple bonsai (also see some in person if at all possible), focussing on examples you like that have similar trunk and initial branch structures to your tree. And when the light bulb goes on, set about to execute your design from this tree.
Bonsai is sculpting trees using their natural growth characteristics.
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