I dunno, if you want to PvP go ahead - rank never was a gateway to PvP if you want to do it, do it. But as a fully vested PL I presume there's friends you've made who aren't PL help them rank up? If not, alliance with others and grind gold perhaps? Or finish bilge rat adventures you might have missed, if any? Complete whatever you might have left of Cursed Sails, if anything? Or, work on achievements you might be missing? Or make friends of others either with or without the alliance system for future content which may be multi-crew dependent? Or get creative and start a twitch stream/Youtube/whatever that does random silliness that isn't copied from others such as how Falcore makes "upsettingly" funny noobisapien videos and such.
Let's not even discuss the things you might get out of being a more social pirate.
Do all this and PvP.
But to presume that simply because you've 'finished' the game all that is left is PvP is to remark clearly how little interest the game offers you. Which is the game's problem, I admit. This isn't even accounting for the millions required to buy everything in the game, which I can understand, since cosmetics are a flavorless carrot for many.
I'm not 'mad' that you finally feel liberated to PvP without loss. But I worry that you clearly fail to see the other virtues offered by playing the game without a PvP focus. Yet, again, no one's loss. The game could use deeper content that isn't a revolving door of events, hopefully additions such as Forsaken Shores provides that. I do know they've mumbled about a new faction in that update - hopefully it's a decent one.