She undoubtedly relishes being a baddie as Vadic, captain of the spiky, scary spaceship called the Shrike.

Source: https://www.slashfilm.com/1265834/star-trek-picard-season-3-major-character-ranked/

Vadic spoke of the universe falling silent and peaceful once more, so the bargain could simply have been that, by allowing the Borg to assimilate the Solids, the Changelings assure the order and control that they always craved.

Source: https://screenrant.com/star-trek-picard-borg-changeling-villain-team-up/

While it's not entirely clear, it does seem that Vadic and her agents are well-connected.

Source: https://www.cbr.com/star-trek-picard-vadic-christopher-plummer-villain/