Is there a recommendation about what path to follow? First thing i did is sail to the main city and am now doing everything inside it has to offer...?

Think of this game as more of an open world adventure as that's what it is. Put off the main story and stay clear of the northern lava  / rocky islands. Yes the main story has this sense of urgency but it doesn't really factor into the rest of the game. The story is just 5-10% of the content, so just put it off because it will force some world changes too soon if you follow it.

 

From Neketaka do what you want and live the privateer life. 

I think the best way is to alternate exploring the city with going out to sea, and switch it up when you feel tired of one or the other. I'd progress the main story up to the step where the objective is to go to the islands to the far NE but then put it off actually going there for a while while you do faction stuff and sidequests. 

I'd recommend switching between faction quests (as in doing one quest for the Huana, than one quest for RDC, one for Vailians, one for the Principi, than back to the Huana again). There are overlaps between the faction stories, and if you do them one full questline at a time you might run into some weird bugs, like one faction sending you to talk to an NPC whom you already killed for another faction.