Hi,
Did you reset the printing system (according to the following article) and re-add the printer? Try again. Check whether the operating system suggests a suitable driver.
Reset the Mac printing system to solve a problem - Apple Support
Add a printer on Mac - Apple Support
BTW, the latest drivers for this model from the Canon support page seem to be from 2017 (for macOS Sierra 10.12). These may or may not work even with a few later operating systems as well. Which printer driver are you trying to use? The 2017 file from the printer manufacturer, or possibly third-party software (such as the experimental Gutenprint MG6120 driver)?
You mentioned wireless printing. If the MG6120 is wirelessly connected to a router, you could of course try Ethernet (the printer connected to one of the LAN ports of the router) or USB (direct connection to the computer), but it will probably not change anything in this case.