It sounds really good! I do think that there are lore reasons why he would sound angrier than usual, specifically because he was so close to taking the plans in Rogue One and they just barely slipped past him. And he’d be unbalanced once Kenobi gets involved, especially.
Real world explanation is probably that JEJ was drawing more inspiration from David Prowse’s delivery based on what we heard of him on the Tantive IV. He then made the role more his own as the films progressed.
Well, if you remember how he was as Anakin, “I hate you!”, it seems natural that in ANH, some of that anger remains. Once we get to ESB, he’s finally starting to calm down.