Sorry but I didn't read through all the posts, so I don't know if this was suggested. It's a very easy fix. Prune off the top immediately below where the 4 top branches converge. Leave the stub because you'll be using it as a stake. Select a lower branch that looks flexible and is oriented at least somewhat vertically, and tie it to the stub, using a strip of towel or something similar that won't cut into the bark. You might need to use more than 1 strip and tighten it monthly if the branch doesn't bend willingly. You could also make a few shallow cuts with a hacksaw blade on the outside of the bend in the new leader if it is uncooperative insofar as bending it. It will make it easier to bend and it will heal just fine.
Prune all growth off the stub above where the new leader is attached, and allow nothing to grow from the stub, it is only there to provide a temporary anchor point.
By next fall, the new leader will be set and you can remove the stub. There will be no branch collar because of the disparity in diameter between the new and old leader, so leaving a short stub is fine. When the new leader adds secondary growth (thickens), you'll eventually be able to identify a branch collar you can use as a pruning guide.
Too, it looks like the primary branch below where the 4 branches converge has a secondary branch very close to the trunk that looks like it is almost vertical. That near vertical branch could also be manipulated to serve as a new leader, unless the camera is playing tricks with reality. It might just be another primary branch on the opposite side of the tree. I can't tell.
Al
Q
Good info on training maple
Q