Considering tendler is rav moshes only talmid who is modern and Zionist, i think it’s very telling that literally everyone else disagreed with him about rav Moshes views on those subjects.
My rebbe rav belsky was close to rav moshe. I’ve met other talmidim too, but the list is very long and tendler is a complete outsider who went so far as to call on the government to interfere with parts of bris milah that rav Moshe held of and that he personally didn’t like