When building something complicated, you first lay the groundwork. Zelensky is refusing the groundwork by using the excuse that the end structure isn't completed to his liking.
Marco Rubio gave a great interview that not only explained the events of that day, but also put the events in the context of the previous 10 days. The rough framework for security agreements were there in the deal. The goal was to give the United States an economic interest and an obligation to protect that economic interest. That is in the deal the Ukrainian legislature ratified, and Zelensky won't sign it. In short, you don't know what you are talking about.