As of year 2020, my WiiU sales estimate : 24.7 to 49.4 million
Please the more detailed post here:
http://gamrconnect.vgchartz.com/thread.php?id=178341&page=1#
Playstation 5 vs XBox Series Market Share Estimates
Regional Analysis (only MS and Sony Consoles)
Europe => XB1 : 23-24 % vs PS4 : 76-77%
N. America => XB1 : 49-52% vs PS4 : 48-51%
Global => XB1 : 32-34% vs PS4 : 66-68%