Apparently Frakes said Season 3 embraces a more 'traditional and optimistic outlook'.
https://showsnob.com/2019/08/30/star-trek-picard-jonathan-frakes-on-returning/
Though I'm not sure how much info he gets about the entire season's story arc, for all we know this could be just for his episodes specifically.
https://showsnob.com/2019/08/30/star-trek-picard-jonathan-frakes-on-returning/
Though Frakes had been barred from revealing any secrets from the Star Trek show, he reiterated that the next season of Discovery embraces a much more traditional and optimistic outlook. He also stated that, despite newer Star Trek shows veering away from Gene Roddenberry’s obvious optimism, as seen in the original series, Frakes doesn’t believe any of the shows (or even JJ Abrams’ reboot) deviated too far from Roddenberry’s initial vision.
Though I'm not sure how much info he gets about the entire season's story arc, for all we know this could be just for his episodes specifically.