Was Yitzchok a Tzadik? Rashi in [Bereshit 28:13][1] says Yitzchok was blind and that his​ Yetzer Harah left him. Does that imply that he had an evil inclination when he wasn't blind?

What about King David? The stories with Bathsheba.

What about Yehudah and Tamar?

(Looking also for an answer according to the Tanya.)

  [1]: https://www.sefaria.org/Genesis.28.13?lang=bi&with=all&lang2=en