Look, if he and the manager don't get on then it's only reasonable that he'd want to leave. It happens at every club the world over, no matter the calibre of player or the type of manager
Why would he sign a new deal if he wants to leave? By all accounts we've stuck a big offer down in front of him and I doubt anyone else would pay him more, so if he's motivated by money then he's got what he wants. However, the fact he hasn't signed it suggests this is about more than money for him
Ultimately I believe that he and Koeman are just not compatible work colleagues. That's no one's fault, it's just a way of life. We've all had bosses/managers that we haven't clicked with for whatever reason. I once left a company because I didn't like my manager and the way he did things. Nothing personal and he wasn't doing anything unreasonable, just his view of the way things had to be clashed with mine so I moved on elsewhere. It wouldn't have mattered if they'd offered me more money, I wasn't happy working with him and would have still left
I'm not sure where this vilification for Ross is coming from. Again, neither of them are "wrong" here, they're just not a good working combination, so it's looking like Ross wants to try his luck with another manager
That's football