Can i connect to the network at the same time from different devices? and who will then get priority (i suppose the first one )? Or, for example, from one device using the linux nmcli utility but with different connection data (ssid, pass)

For example:

nmcli device wifi connect RouterSSID password 12345678

and at the same time run another command with different connection data

nmcli device wifi connect RouterSSID password 99999999