What progress is being made in the US-Russia talks regarding ending the war in Ukraine?

Secretary of State Marco Rubio reported that the two sides agreed to appoint high-level teams to work toward ending the war in Ukraine in a way that is 'enduring and acceptable to all sides.' For Russia, simply having this meeting and the recent 90-minute call between President Trump and Vladimir Putin represents progress after years of isolation due to sanctions. However, Ukrainian President Zelensky has expressed concern, stating his government 'will not recognize any agreement about us made without us,' which raises questions about the legitimacy of these negotiations happening without Ukrainian representation at the table.