I have to take issue with ur idea that gedolim say empty compliments. They tend to say what they mean. In any event, the compliments and things gedolim said about the Rebbe are not measly little things and I think u should look into it before assuming such. There are a few volumes of the Rebbes relationships with gedolei Yisroel. Many stom people don’t tend to read the Rebbes sichos and mamaarim and for that reason don’t know him for gaoness. But it’s silly to say that because of that he wasn’t a gaon. But the chief rabbi of montreal, Rav Hirshprung, knew shas like the back of his hand. I personally know a rabbi who was in his class, him and a friend decided to take a piece of ripped tosofos out of sheimus and see if Rav hirshprung knew where it was from Baal peh—he did. This same Rav hirshprung said that’s if u want to see real gaoness u will read the footnotes in a lukutei sichos. One of a million.
Not sure what ur point is about the Rambam, if u could clarify