Disputes among the Rishonim in the Explanation of the Gemara

Peace and blessings to the late Rabbi Shlita
As is known, in the Gemara, there is the well-known explanation of “these and those” regarding disagreements between Tannaim or Amoraim, but what do we do when there is a disagreement between Rashi and the Tosafot (for example) in explaining things in Tannaim, when it is clear that there is no chance that both interpretations together are correct, so in fact one of the interpretations is incorrect? When I struggle to understand Rashi and most of the Rishonim interpret differently, is it possible that the Tannaim’s intention was not the same as Rashi’s and I am learning incorrect things?
There is an explanation (perhaps from the prophet) about places where there is a dispute created due to different versions, that even if only one is correct then we have at least gained from knowing what the opinion of the first one (who had a distorted version) was. But even if this is true, it does not apply to the case I cited at the beginning, because Rashi did not come to express his opinion but to explain the opinion of the Tanna – what he meant.