You're looking at these moves in isolation from each other but you have to look at them in combination. Each move makes individual sense, but they don't make sense when done in the same off season.
In addition, moving up to pick #9 with a bunch of picks isn't drafting BPA, it's moving up for a targeted player because you think you have a need at that position.
And, I get that Cousins made sense for them when they signed him (assuming their medical was right and his injury fully heals). But, once you make that deal, moving up to take a young QB at #9 with a bunch of draft picks does not make sense.
It may work out for them if Penix turns into a star, but it's still a strange way to go about it, and I think he's going to be mid-tier QB at best.
It would be a different story if Penix fell to them at their pick and they had him rated as BPA, but that is not what happened. And the vast majority of people did not have Penix as BPA at #9. Personally, I had McCarty and Nix ahead of him and I think I would have taken Rattler over him.
But, again, if Penix turns into a star then they were right and I'm wrong.