He's someone who looks centrist but is solidly in Francis's camp.
I think he was elected for a singular purpose and that is a specially forged dagger aimed at the Anglosphere Catholic right.
I think this is why Tagale lost influence, Francis was increasingly concerned with the heretical tendencies in Tradcaths and has moved to crush them once and for all before they can schism.
Basically Vance may have killed Francis but Francis had his revenge stacked up long before.