Canon printer driver issue
I don't know where to find the Linux drivers for Canon printers. The official Canon site doesn't even have a Linux driver for my printer. Luckily, the Gutenprint driver works well for Canon printers. You can install it as follows:
sudo apt install printer-driver-gutenprint
Then, connect your printer via USB to the computer, and go to Settings > Printers.
If you don't see your printer there, add it. If you see the printer, click on the gear icon next to it, and select printer details. On the new window that opens up, select Select from database...
Find your printer model under the Canon drivers.
Once you save that, your printer should work :)
I tested this solution both in Ubuntu 18.04 and 20.04 using a Canon PIXMA MP470 series printer, and I could see an entry for the MG2500 series printer too.