I still have Folke Deluc (initial tutorial navigator) in my crew after 11 years of gameplay time (1662) on this iteration.
I turned him into a great boarder and an overall good quality officer.
I just rotated him into different positions over time for diverse experience, and took the shared experience perk REALLY EARLY.
Remember longevity in your crew has value over time.
I don't really care you cannot use him as a companion (ship captain).
You can give weapons, equipment, and amulets to him and use him as such to use, although as stated you have to pay him off as an officer more often than most even at max loyalty. The amulet direction is actually recommended, as this helps him be more viable early in the game especially as the navigator until his other skills come up to par. He gets switched to Chief Gunner after Charles reaches 45 navigator, then goes on purser, then boatswain. By that time, the rest of the officers are filled, and you rotate accordingly, except shipwright.
BTW, I still after all this time sail a 4th rate ship, "Sea Wolfe" to keep costs WAY DOWN, and bank the rest. I do have a 2nd rate Heavy Frigate on Isla Mona for needed missions. The "Sea Wolfe" can handle most encounters except large convoys, Pirate Hunters, or Gentlemen of Fortune easily. I don't like the tactical maneuvering of large ships as it makes them hard to fight or run, taking the brunt of damage, even when fully upgraded. I am sure I will upgrade to the "Dog of War" or Gryffindor eventually through the main quest again. I am leaving the Caleuche for last this playthrough.