The Section 31 movie is set to begin filming in January 2024 with production lasting into March. Michelle Yeoh is the star of the movie, reprising her role as Emperor Philippa Georgiou from Star Trek: Discovery who was sent back in time by the Guardian of Forever.
As Screenrant mentions, the official press release for the movie says that Emperor Georgiou will join "a secret division of Starfleet tasked with protecting the United Federation of Planets." And since she was already in Section 31 during Discovery, there's speculation that this could be a prequel movie. That, of course, could put her in any timeline, including Star Trek: Deep Space Nine which was set in the 24th century. If that's the case, this is the perfect opportunity to bring in a character who was morally opposed to the nefarious Federation agency—Dr. Julian Bashir (Alexander Siddig).
Though an attempt was made to recruit the doctor, Bashir's morals prevented him from accepting the assignment. Instead, he set out on a mission to expose Section 31 as a corrupt agency that needed to be disbanded. And that's why he should be brought into the movie.
As someone who walked the path between good and evil, Georgiou could use someone looking over her shoulder, someone who isn't afraid to call out the bad parts of Section 31 and even realize the good parts along the way, if that's the way the movie goes. Dr. Bashir would be the perfect agent in the shadows to keep watch over the agency and to intervene when the division was going overboard.
Siddig confirmed in December 2022 that he has not signed on for any Star Trek project, but being that was a year ago, things could have changed. Perhaps the producers have seen what a difference he could make in the movie, even if it's just a small part. Every dark organization needs a conscience.