Ask him. I would say I am in my prime in 2024 and I am 4 years older than GSP. He has had no major injuries he still trains all the time so yeah 42 he should be in his prime.
You’ve established retired athletes are not in their prime so it would be foolish to ask him.
In your prime you had a full head of hair and you made 500k in one year. Today you are bald and unemployable.
You are on a rapid decline.