Blackbeard is the one who
> Waited decades in Whitebeard's crew to get the right df
> Wantred to become a Shichibukai to fool the World Government by planning a coup in Impel Down to get level 6 prisoners as his subordinates
> Used the MF war to get the gura fruit from Whitebeard
And currently that same Blackbeard
> Waited for the right moment to take WCI's poneglyph, the poneglyph reader(Pudding) as well as Law's poenglyphs post-wano, while planning something in Egghead
> Looking for the guy with the burn scar to get his poneglyph
> Trying to strike a deal with the World Government to create a conflict between them and the population over the possibility of being officially granted similar status Kingdom Kings get, but for Beehive
So looking at this, it's pretty clear that Blackbeard is aiming at something beyond pirate king. Receiving the king status is most likely some kind of plan he is preparing after becoming pirate king to ultimately take Imu's place and overall becoming the actual king, not just of Beehive, but of the world