PMP Practice: Determine appropriate feedback approach

Diego Villanueva-Cruz is the scrum master for Dumpling Nebula Games, an indie studio building a roguelike dungeon crawler scheduled to launch on Steam in six weeks. During the current sprint retrospective, two senior developers, Kenji and Dante, voice conflicting concerns. Kenji, the lead gameplay engineer, argues the team should slow down feature development to mentor two junior developers who joined three sprints ago — he believes their code quality issues are creating technical debt that will hurt the team's long-term velocity. Dante, the graphics lead, counters that the juniors are learning adequately through code reviews and pair programming, and that reducing feature output now will jeopardize the launch date, which the publisher has tied to a major gaming convention. Dante notes the team has already cut two planned features and cannot afford further scope reduction. Both developers are highly respected, and the rest of the team is split on the issue. Diego has observed that the juniors' merge requests do require significant rework, but their improvement curve has been steady. The product owner has indicated the current scope represents the minimum viable product for a successful launch. What should Diego do to best support team performance while balancing these competing priorities?