For me it was the complete opposite. I thought he did a wonderful job with acting. The argument he had with the starfleet officer was so intense but he also had really touching scenes with Troi, Soji, and Data.
I tend to agree. Really, there wasn't much I could fault with the acting from any of the characters in this series? I thought all of them played their roles well. Soji, especially, did a good job going through that whole process of trying to discover who she really was - complete with the anger, confusion, distrust, hope .... all of it.
I don't think it's relevant to compare Picard's character to his role played in X-Men movies. Professor X and Jean Luc are not supposed to be the same people at all! (FWIW, there's a movie out there called "Safe House" that stars Patrick Stewart in more of a comedic role, where he really manages to break out of the "mold" I think we all tend to typecast him in. Worth checking out if you never saw it and like his acting.)