magnus
I see why you might think that Viswanathan is the best, but Praggnanandhaa is definitely not. Nor is Hans.
Above are simply the best players because they were world chess champions. That's in historical order, Steinitz was the first world chess champion ever, in 1886.
Lasker held the title for 27 years (world record), Kasparov for 15 years, so these two players are special.
Other way to look at things is the peak rating:
I'd say 2800+ is an achievement only 14 people on Earth got so far and right now only 2 people hold 2800+ rating (Carlsen and Nakamura).
No Lasker in this list, although some researches compare calculate his peak rating as something close to Kasparov's.
For currently best rated, here's October 2024 top:
I think Magnus Carlsen is the best.