Thank you for the information, Anney.
It looks like everything is correct. If there is a problem with the driver (which is said to work with macOS 12 Monterey), you may have to contact OKI.
Could you possibly connect the printer's Ethernet port to one of the LAN ports of a Wi-Fi router, just as an experiment? The iMac should be connected to the same router (wirelessly, or via Ethernet). If you then, after another printing system reset, try to add the (now network) printer, any change?
As always, make sure that you have backup copies of all important files before testing anything.