Chapter 2 hands John to the High Table, and the clearest evidence is how the next film opens: John Wick 3 begins with John having killed a member of the High Table inside the Continental, which breaks the rules of the hotel. He is declared excommunicado, gets a short grace period, and then a huge bounty takes effect. He starts that film hurt and on the run in Manhattan.
In my opinion, that handoff is what makes the series feel like one long chase rather than separate stories. The first film is a revenge job with a small circle of enemies, the Tarasovs. Chapter 2 is where the rules of the Continental stop being background and become the plot, with Santino D'Antonio and his sister Gianna pulling John back into a world he had left. Winston Scott, Charon and the Bowery King then carry that world into the later films.
So, what was the point of John Wick 2? It could be argued that it is the bridge between the lean 2014 original and the two bigger films that follow. Chad Stahelski directed all four main films, and the growth shows in the numbers: 101 minutes for John Wick (2014), 122 for Chapter 2, 131 for Chapter 3 and 170 for Chapter 4. The $40 million budget here also made room for a second shooting city, Rome, after New York.
Perhaps that is why it plays differently from the original: it trades simplicity for scale. John Wick 4 then has John deciding to take the fight to the High Table directly, which only works because Chapter 2 built the organization into something worth fighting.