He's 76 and has had some health issues, and hopefully he doesn't have the need to step down. Conservative justices are needed. Kavanaugh, Gorsuch and Barrett, though younger IMO have been a huge disappointment and quite frankly our current GOP Senators have been a huge disappointment as well.
So .... IF he were to step down now, would a younger true conservative justice be advantageous as to replacing him in the future? I'm not so sure.