I mean in saying that, Barty will most likely get her 3rd YE#1 this year unless Sabalenka has a great run to end the year.
Although, looking at 2021, Barty is the clear WTA player of the year.
In terms of the 4 slam champs.
Osaka won the AO and did nothing else
Krejcikova won RG, Strasbourg, Prague, finalist in Dubai, QF in Cincy and Dubai
Barty won Yarra Valley, Miami, Stuttgart, Wimbledon and Cincinnatti.
Raducanu won USO and a 4R at Wimbledon
Nobody really comes close to Barty.
1 slam, 2 WTA1000's, 2 Premier titles + a 1000 runner up
Sabalenka, Muguruza and Swiatek each won 1 WTA1000 and 1 500
Badosa won 1 WTA1000 and 1 250
Krejcikova got a slam and 2 250's