I started as a Federation Bounty Hunter, and worked my way up to my own battleship(Marauder) and also have the relevant skills for fleet combat. What do I actually do at this point? I've been helping the Federation invade/defend systems so far, and that seems to be all I can really do?

It looks the way.

The overall goal is to help your faction win the war by having it hold enough systems. For that each class has different tools.

Officers and (I think) Bounty hunters can control fleets and attack the enemy directly (you can also raid pirate bases for money)

Traders (fleet and free) can own factories and with all the cash they get buy massive amounts of war bonds

Pirates and Smugglers can create their own faction (no idea if you can win with it by holding enough systems)

In topic "Piracy as a career?" the author mentions as an independent they never won a war. I changed from independent trader to Federation Admiral when a governor offered. From that point, I'd guess I poured 150 - 200 million into war bonds. The Federation didn't grow a single system. Maybe defended well against constant attacks, but no progress.

I don't see a path for pure traders in the endgame, which is annoying since it's the path I like the best. Wondering if others have found an endgame for traders?