I’m using Ubuntu Focal (20.04), update time: 2021-11-22.
My router is configured for WPA2/WPA3 and works fine for all my devices.
Just after I installed the OS when I try to connect to wifi with nmcli d wifi connect "My_SSID" password "My_Password" it rises an error message.
I found out I could use nmtui command (a more “graphical” tool) to edit the just created connection to my wifi and change it to force use of WPA2.
Now wifi works!!!
Later I changed back to WPA3 and now it also works. Weird behavior!