Although a lot of pundits thought she got very lucky with the judges' decision.
Regarding Joshua, this is a big concern. Ruiz is a hard hitter, but so is Deontay Wilder, who AJ's been hoping to fight for a long time. I'm not convinced that Joshua's punch resistance is as good as it ideally would be, and so he needed to use a much better defensive strategy than he did. With this kind of approach against Wilder, I'm sure he would have suffered the same fate.
In the long term, this ought to make fights against Wilder and Fury more likely. In the past, Eddie Hearn's been pricing AJ out of the market, but his bargaining power has now dropped. There's no way he could get away with pushing for a 60/40 purse split in Joshua's favour now, even if he destroys Ruiz in the probably rematch.
Fights against Wilder or Fury at Wembley would still be massive, but not to the extent they would be if this hadn't happened. The fact that Joshua was talking this weekend about a unification fight with Wilder in September suggests that he never even entertained the thought that Ruiz could beat him, and that's come back to bite him, just as it did with Lennox Lewis when he saw Hasim Rahman as a stepping stone towards a showdown with Mike Tyson.