A separate Borg Collective formed when Agnes Jurati merged with a Borg Queen in 2024 and persuaded her to assimilate only the willing, which returned in 2401 to ask the Federation for membership.
This Collective originates in the second season of Star Trek: Picard. Stranded in 2024, Doctor Agnes Jurati is partly assimilated by the Borg Queen of a dark alternate timeline. In Hide and Seek she convinces the Queen that a Collective built on cooperation rather than conquest would never again face the loneliness of defeat, and the merged being leaves Earth in La Sirena.
Four centuries later, in Farewell, a Borg vessel emerges before a Starfleet armada in 2401 and its masked Queen reveals herself as Jurati. Her ship and the fleet combine their shields to contain a huge energy discharge from a newly opened transwarp conduit.
She then requests provisional membership of the Federation so that her Collective can stand guard at the conduit against whatever created it. Picard, who had trusted her with control of the fleet, supports the request.