As part of the graduate program, it is expected that graduates will move from APS levels 3 to 5 during the year-long program with opportunities to progress to level 6 and move to different after that if successful in applying internally. Such applications all must follow a merit-based official process, so I would say the opportunities for promotion and progression are abundant and fair.
It does seem like in most areas of the department that promotion is accessible to those who are passionate about their work.
Anxious about ability to get to the executive level quickly. I anticipate quick promotions to the APS6 level.