I think a better story choice would have been a surviving clone recovers Fetts armor (with Fetts corpse inside) and goes on a voyage of self discovery about who he is as a clone, who Fett was as "clone prime", who Janjo was as their 'father' and struggles with imitating Fett and being his own 'man'. We the audience could even be misled that it WAS Fett who survived, but we get a reveal that it's actually another clone who first tried to pass himself off as Fett, but doesn't want to keep doing it. There is a lot to unpack about being 1 of THOUSANDS of literally identical beings, being raised with a brainwashed purpose, and how to have an identity apart from the strong societal pressures on you. Far better story than the heel turn Fett makes IMHO. The actor being so old now should have been more attributed to the clone process failing, something Boba shouldn't have had because he grew as a child, not force cloned into an adult. That would have added time pressure to make his mark before he died.