Usually setting the mission and going to space points you in the right direction but it seems this is a bit hit and miss with next.
Sometimes youll have two missions about recruiting the same person, one for the overseer, and then one specific to the new recruit, try selecting and going into galactic map for eaxh mission, if it doesn’t locate on map visit a Vy’keen system.
I’ve found locating specialists much easier with next now thatthe space stations are loaded with NPCs, one of them will usually be a specialist, sometimes in the room beside all the upgrade shops. Personally I found my armourer by chance on first trade post I hit on a planet in a vykeen system.