Pretty sure it's Taylor. His 15 page monolgue before the committee is loud and clear. He started in the Trump administration in June of 2019.
It appears he kept profuse notes (the Comey method), trying to entangle everyone in his pursuit of his imaginary "quid pro quo" scenario. More than one person told him to buzz off.
It could be Taylor as WB, or just instigator. Remember that the WB has to take a seven figure book deal for the team and there a lot of deranged junior-deep-stater Trump haters out there who would do that.