One way to do that which might be doable has nothing to do with Fett but everything to do with the current plot of the film.
Solo awakens blind and learns to see the world in a new light.
He is reborn.
No longer even pretending to be solo.
It might be possible to turn Han's new rank as a Rebel general into something bigger.
Maybe by shooting footage of more troops and taking dialogue from Ford's other films.
That way his raid on the dish becomes a turning of the page for Han instead of just stuff he was doing in between the the explosions and the sword fights.
Make it a risky endeavor for him.
Make a big thing of Leia getting shot etc so it book ends his rescue when he finally saves the day.