I daisy chained some commands together into a script that MIGHT help with automate the manual process a bit. It isn't anything too complex and there might be better, more advanced ways to generate the needed topology but this should get close to the same results you're getting manually. When executed it does the following:…
That's how I would do it. *shrug* I would probably detach that n-gon and tessellate/optimize it with protect boarders turned on then weld it back into place. Unless pro-optimize works on a selection of tris instead of the whole mess, if it does then forget about detaching it. There might be some scripting mastermind out…