The whole Counsel thing is kind of a mess on both sides.
Counsel felt betrayed when the whole Hader trade went down last year. The front office kinda messed up on that deal and I believe it soured Counsel to the front office. That's why he went into the past season on a lame duck contract despite the Brewers offering an extension.
Now, Counsel, for his part should have manned up and told the Brewers he was unhappy and wanted to leave after the 2022 season. It would have allowed both side to move on earlier, rather than wait for his contract to officially end.
He's leaving for good reasons - more money for himself, and for a team with relatively unlimited funds who doesn't have to sell it's free agents, unlike Milwaukee who will never have the resources to keep all its best guys and sign big money free agents to fill in the gaps. He sees this as a path to a World Series.