I generally don't trust Barnes on these things. He's gotten some major cases obviously wrong before, like the Ahmaud Arbery case, IIRC. More, I'd say I highly doubt that. The dude's ruled for Trump enough that he's not a plant. Most importantly, if he was a plant, he should have just said that the stuff said by Wade to Bradley was covered by Attorney Client privilege. It would be impossible to deny that, as all the stuff was reviewed in private without oversight. Yet he ruled for Trump.
No, the big issue isn't him being corrupt, it's him being worried about having to work with Fani Willis after this case on all kinds of different cases. He probably wants something clear and obvious that he can point to, otherwise his daily work life will be hell. The phone records might do that.