I’d say two movies is probably the best option. The only way you could possibly get one movie to work is by cutting Chapter 9, and that would make it kind of weird how Mando suddenly has Boba Fett’s armor given how important it becomes later on.

Here’s my idea for a two movie structure:

Episode 2
THE SEARCH
Chapter 9 (with cuts to reduce references to Chapter 5), Chapter 10, Chapter 11, Chapter 12
Approximate runtime: 2 hours 29 minutes
If keeping post-credits scenes, have Gideon revealing the Dark Troopers be the post-credits scene.

Episode 3
THE TRIUMPH
Chapter 13, Chapter 14 (once again trimmed to remove Chapter 5 references), Chapter 15, Chapter 16
Approximate runtime: 2 hours 27 minutes
If keeping post-credits scenes, keep the Boba spinoff tease after the credits.

It’s not a very creative edit, so I could understand why one movie would be more interesting. But I think two movies makes the most sense from a storytelling point of view.