Further thoughts on Arabian’s idea: If we do just end Book 1 with Mando flying to space and cut to black there, then it lets you potentially start Mando’s story much later in Book 2, allowing Boba to take the lead and with less backwards and forwards. Alternatively/additionally, maybe you could actually have the Boba overlap point a bit later - Mando could be on Tattooine for much longer, leaving Fennec for dead, before Boba comes to Mos Eisley and nearly bumps into him, potentially only then heading out to the desert to find Fennec. Pelli’s dialogue might be modified at the point where Boba sees her walking with her droids, to discuss Mando’s quarry, to give Boba the hint to go save her. Then Boba and Fennec’s plotline could interleave with Mando’s plot on Nevarro, to keep both in focus.

Also, I made my own cut of your current Book 2, which removed Greef’s intended betrayal and the fireside scene (Mando just says “I have a plan” at their first meeting and we cut to him in cuffs meeting Werner Herzog), and also removed Mando needing to take off his helmet (he just “gets his head dinged” but then after the team open the sewer vent he’s walking - with help, through the tunnels). I found that both of these worked nicely to improve the pacing in that sequence.