Yeah, Vader in the first SW movie was more like hired muscle instead of the Emperor’s right hand man. He’s subservient to Tarkin and he’s openly mocked by Imperial officers throughout the movie. Certainly not someone who’s basically second in command of the whole Empire.

I’m sure something in the canon explained its way around this, but it’s obvious that George Lucas didn’t have the backstories of these characters planned from the beginning like he’d claimed.