Comparing ELO like that is silly. Kasparov had his final championship victory in 1995, and it was during the period in which he had left FIDE. Karpov won the FIDE championships (which of course Kasparov didn’t compete in), in ‘93, ‘96 and ‘98.

You could pick a similarly silly way to compare their careers by comparing their peak ELO. Which for Kasparov was 2851, and for Magnus 2882 (highest in history incidentally). Which is a rather large difference given the ELO system gets so wonky at that level that you can drop in ELO after winning an event (as I believe happened to Magnus after he won the Norway tournament this year).