The Admiral's crews are carefully chosen for ideological loyalty.
Her faction has certain academies on certain planets where its views hold sway among the faculty, and the enlisted crew are drawn largely from political activist groups aligned with her views.
Inconveniently, what they aren't chosen for is personal loyalty to the Admiral herself.
So her flagship, the Ophiuchus-class supercarrier Bhavacakra, under the Admiral's personal command, is making this journey alone. Fleet logistics would invite too many questions.
Not that this isn't a huge amount of manpower and firepower. The point isn't to keep the information secret after this is done. A two-person trip in a single-occupancy yacht would be the only way to do that. But that would be the wrong kind of projection of force.