Disagree, he was magnificent in Pep's last season pretty much every time I watched them. That Bayern team was ridiculously good and it's a shame they didn't win the CL that year, team who could play multiple systems in one game and do it almost flawlessly. They were pretty unlucky in that game against Aletico, where Alaba did make quite a costly mistake in the end.
Last year maybe not as great but still think he plays at such a high level. Ancelotti is very different with what he asks and where Alaba will have been used to playing all three roles in one game, depending on the state of the game, where the ball is, what the opposition are doing I think Ancelotti likes it a lot simpler and maybe Alaba is still adjusting back to that. Both different managers, equally as good in their own ways.