I’m not sure how you could remove Grogu from Tatooine without resolving the whole rancor rampage thing.
The rancor rampage can actually be cut by having Boba v Bane be the climax. Then cutting to the Fennec assassination scene.
Having you considered replacing the ‘Cobb Vanth in bacta tank/MOD-ifier guy’ scene with the humorous ‘Grogu getting a joyride in Mando’s ship’ scene as the post credit, therefore giving a more serious ending?