Maybe a bit of both. He's certainly improved as a referee since they put him in at a very young age as some kind of experiment.
The Foden free kick was purely guesswork. Their player went down first, so give them the free kick, with no clear knowledge of what really happened. We only know because of TV replays. Not bent, just bad refereeing, but it can be argued that he was favoring the defending team, and I've no problem with that. Most referees would do this so as to reduce the chance of a goal coming straight from a refereeing mistake.
The two goal kicks instead of corners? Just mistakes. Every referee makes mistakes. Every player makes a mistake sometimes. I can live with mistakes, so long was they are balanced. When they favour the same team, you have to start asking questions, but two is not a large enough sample to question his integrity.
The penalty to Sterling? Why give it in the first place if he was biased against us? Correct outcome.
The penalty to Gundogan? It would have been harsh.
The penalty to Bernardo? Definitely a penalty. The fact that he took two more steps before going to ground means nothing. The only question is, was he fouled inside the penalty area, and he clearly was. It's fine if he didn't give the penalty, because VAR is there to correct these obvious errors (as it did in the first half). So I would argue that Atwell showed incompetence rather than bias. VAR, on the other hand? Whoever that was needs to answer why no penalty for the Bernardo incident, if VAR reviews all contentious decisions.