Surprisingly, I think Darth Vader never sits down in Return of the Jedi. Objectively.
WRONG! If you watch the deleted scenes, he CLEARLY sits down right after arriving on the Death Star in order to contact Luke and persuade him to join the dark side. You utter imbecile. You should be ashamed of yourself. 😉
You’re right.
I guess the only time he sits in ANH is in the TIE Fighter? I’m pretty sure he always stands in the conference room