Here’s why Trump releasing his medical records doesn’t work for me.
Even if he had surgery, and there are were x rays proving beyond any reasonable doubt that Trump had this affliction, people like you would still say that the records were forged, or that the treatment was still just a ruse.
I don't know if you are old enough to remember that time, but it was very common for those with the resources to do so to do just this to avoid serving.
Regarding the David Duke endorsement, the problem isn't the endorsement, but with Trump's ambivalent response. And, Trump's claim that it was due to a bad earpiece is absurd, since he repeated both "David Duke" and "white supremacists".
Perhaps Trump is old and tired. Perhaps he's suffering from early-stage Alzheimer's. But it was an embarrassing performance, and the piranha like attacks of the cultists don't help your cause.