Here’s the list of what Luffy did so far.
-Luffy defeated Shichibukai Crocodile.
-Then he defeated Shichibukai Moria.
-Luffy defeated the strongest CP9 agent Lucci before the timeskip. They covered Luffy’s actions in Alabasta and said Marines defeated Crocodile; they also hided Shichibukai Moria’s defeat; the world only knows about CP9 and Ennies Lobby incident.
– Luffy defeated Shichibukai Doflamingo.
– Because of Luffy’s actions, the Government decided to demolish the Shichibukai system.
– Luffy then defeated Yonko Commanders Cracker and Katakuri. Morgans (not the World Government) declared Luffy as the Fifth Emperor.
– Luffy even awakened the Gomu Gomu no Mi previously known as the Hito Hito no Mi, Model: Nika. He then defeated Yonko Kaido, who is the strongest pirate, and saved Wano. The World Government finally declared Luffy as fully fledged one of the Yonko. The new wanted poster shows that Luffy is Joy Boy.
Here’s the list of what Blackbeard did so far.
– The world don’t know Blackbeard doesn’t sleep, or wounded Shanks’s eye or killed the 4th Division Commander Thatch, or that he destroyed Drum Island, so it doesn’t count.