His acting felt fine. There was never a moment that stood out to me as "This is bad acting!" So, if I'm not thinking that, then I don't have a problem on the surface level. Beneath the surface...
In "Remembrance", when he was arguing with the journalist who was trying to pigeonhole him into a narrative corner, he sounded like Picard. An older Picard, but Picard. When he's arguing with Beverly about Jack in Season 3, that also felt like Picard. Probably him at his most Picard was when he was briefly in command of the Titan. Complete with a Captain's Log.
On the other hand: The lines blurred between Patrick Stewart and Picard during the TNG Movies, and it continued into PIC. I'm not going to deny that. I think the same thing happened to William Shatner and Leonard Nimoy. I blame it on the actors becoming a little too comfortable in their roles and not trying as hard because they think they don't have to. Especially when years turn into decades. At some point it became automatic, then it became so automatic they started taking it for granted and didn't notice they should try to keep the characters a little more separate.
Patrick Stewart's voice and energy level, I'm not going to hold against him. He's over 80. I'm not expecting Picard In His Prime. The whole point of the show is that he isn't, and that's why he needs the other characters.