I get the instinct to ask this as a fan. I’ve wondered the same thing.
But I think the presumption of the question is that this question is best answered not by the athlete themself, but by other people’s perception of them (I.e., records v. peers and public esteem); and that what other people think of the person matters most rather than what the person thinks.
I think that is an incorrect presumption.
Therefore, I think the question itself - and the options offered are not really answerable except to say:
“None of the above”.
The best answer on retirement for any professional athlete (who has the choice) is that they should retire when they feel either lack of enjoyment or lack of productivity reach unsatisfactory levels and they just don’t want to continue.
I think as long as Fed, or Rafa, or Novak still want to play and can play- they should keep playing.
For Federer, I’m convinced after hearing coaches and friends and commentators say again and again that they’ve never met anyone who loves the game and the culture of the game - the tours and travels - as much as Fed, that this is true.
I think his longevity and his strong desire to come back after bad injuries and inspite of the fact that his greatest records are gone and very likely unrecoverable, bears this out,
He clearly loves tennis and as long as he wants to compete, I say he should.
It’s his life, not the public’s.