A famous and renown band leader can’t play and tour anymore and looks back at when it all started in his childhood

If you want the conflict to be in the band leader’s young life that he’s looking back at, I would consider writing it without suggesting the older guy is looking back at his life. Whilst it helps tell a story, the bulk of the plot is happening in the past. Alternatively frame it like “A famous band leader reflects on his career where he blah blah blah blah”. This way, you’re almost using the present tense as “world building” – it’s needed to understand something about the plot.

Hope this helps.