The one who disagrees with his master

The sources that existed in the past were fewer than today. Even if it was passed down orally. The main point of examination is the methods of learning from the Bible. And the judgment. And in this we can see it as it is today. So is the Rabbi's answer that what is said in the Gemara that one who disagrees with his rabbi as one who disagrees with the Shekhinah is only in the case that he did not reach the teaching? Because there is no mention of that. Of course, those who learn it from those who disagree with Moses. It is possible to excuse that they did not reach the teaching regarding him. But the fact that they simply learn it from every rabbi and did not mention it is difficult. And Korah and all the heads of the Sanhedrin there certainly reached the teaching had it not been for Moses.

However, I have now seen that there is an interpretation that one who disagrees with his rabbi is not to disagree with a halakhic ruling but to establish a competing beit midrash for himself like Korah and his party who disagreed with Moses and separated from him. In doing so, he breaks away from tradition and connection to his own sages, and this is the prohibition. Perhaps this is a better answer to the Rabbi's method.

Are there any who disagreed about their rabbis? And why do we need evidence for this? Didn't the Ritva, the Ra, and the Rashba disagree about the Ramban? Even the Tur occasionally disagrees about his father, the Ra.