“The halachah is about social events of simchah, while R Nachman is talking about personal שמחה. No contradiction.”
Likutei Moharan is not a sefer halachah. Whether or not there’s a contradiction is irrelevant; it’s not comparing apples to apples.
“Yes it is. You even know it is, so you have to twist the words משׁנכנס אב ממעטין בּשׂמחה to mean the opposite of their meaning.”
Seriously. With all of our creative minds combined, we never came up with anything that far out on the YTC Teshuvos thread.