And just for kicks I looked up the top 24 leaders in All-Time Walks to see how Soto might compare to them. The only players with a higher BB-rate than Soto are Ted Williams [4th overall but tops in pct at 20.64% !!!] and Barry Bonds [20.29%]
The remainder of the top ten in Rate are: Babe Ruth, Eddie Yost!!! (the original 'Walking Man'), Mantle, Thome, Frank Thomas (Big Hurt), Joe Morgan, Rickey Henderson, and Harmon Killebrew. 23 of the 24 have walk rates above 10% with only Pete Rose (9.86%) dipping below 1-in-10 but making up for it in volume.
No one on the active list is all that close to cracking the top 24 in walk totals: Carlos Santana, Bryce Harper, and Andrew McCutcheon (top three active players) are currently in 40th, 61st, and 69th place on the all time list.