Every single Marvel Cinematic Universe project to have arrived since Avengers: Endgame has referenced the Blip in some fashion, which makes complete sense when it’s the biggest thing to have ever happened in human history, at least within the in-canon world.
If a huge purple alien snapped his fingers and erased half of all life in existence for five whole years before a team of superheroes used time travel to bring them all back in the blink of an eye, you’d bet your ass people wouldn’t stop talking about it.
Marvel doesn’t have to explain what happened to every major character that was unaccounted for during the Blip, but in Hawkeye, it did significantly improve Yelena Belova’s revenge-fueled arc. In the case of Vincent D’Onofrio’s Kingpin, though, he’s been putting the pieces together himself, as he revealed in an interview with ComicBook.
“I think he lost his power. I think that his empire fell because all this otherworldly stuff was going on. Given the opportunity, he might have been able to even grow his empire during that stage, but he wasn’t given that opportunity. So I think, as far as Hawkeye goes, he’s on his way back, to grabbing back what is his. It’s clear, I think, from the scene with Vera [Farmiga] and the scene with [Alaqua Cox’s] Maya, all the scenes with Maya, that his mind is set on being the king so that’s what he’s gonna be.”
That would beg the question as to who ran Wilson Fisk’s criminal empire while he was gone, because Hawkeye made it abundantly clear that it wouldn’t have been the Tracksuit Mafia. It’s an interesting thing to ponder, but you have to admire D’Onofrio’s dedication to the part after taking matters into his own hands to conjure a suitable backstory for Kingpin before he returned to the MCU.