So, just to clarify, this is how I would like to see things work by the end of the Beyond Season:
A newly minted Commander rocks up in Federal Space.....eager to begin a career with the Federal Navy. First of all, they need to become Cordial with the Federation, in order to unlock the Federal Navy Mission Board.
Once they can access that board, they will find a range of "Rank Appropriate" military missions, all of which will push the Commander closer to their next rank. At Ranks None-->Recruit, these missions will probably involve little more than Data Delivery, various haulage missions....albeit with a military flavour to them. When the Commander is ready for their Promotion, they will get a Chained Mission they need to complete. However, this mission will automatically appear as soon as they are eligible for promotion.
At Recruit rank, Commanders gain access to Federal Military Outposts, whose mission boards contain a larger number of Military Missions than Civilian Boards do. As the Commander rises up through the ranks, they will get access to more difficult & dangerous missions, & will gain access to Military Settlements, then Military Stations, then Naval Shipyards. Each of these military facilities would also play host to their own set of Traders, Engineers & Outfitting Services-the latter containing modules only available to Military Personnel (light weight, extra-long range Military Grade FSD's; Military Grade Weapons etc).
However, once you're in the military, you need to keep your nose clean. Higher military ranks would demand you remain Friendly or even Allied with the Federation.......& crimes against the Federation would cause you to lose Reputation, which could in turn lead you to lose rank. Gaining a Federal Bounty would result in an instant demotion, & you'd be locked out of the Naval Mission Board until that Bounty was lost.
At least, that is how I would like to see it work!