Pixma Pro 9000 Mark II: photo cyan stopped printing one day

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Randomly one day, photo cyan stopped printing. It printed out just fine for months, and still had more than half the tank left. I did a cleaning, then a deep cleaning, then a head alignment, but the color doesn't print out in the test sheet. The printer is registering the photo cyan as shown in the supply level (I switched out the cartridge thinking that that may be the problem and the supply level changed to full). I also did a reset where the cartridges were removed, the print shut down for 10 minutes, replugged, cartridges replaced, and the printer recleaned... to no avail. What could be the problem? 

Thank you ahead for the replies and for getting closer to the solution. 

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Just to add more info and context, the printer was purchased in 2013. 

And when I printed out photo cyan before changing the cartridge, it printed out grey. After, I changed it, printed out pink. 

I'd like to have the printer checked out by a professional, but there doesn't seem to be a Canon printer repair technician anywhere... as mentioned, this is the first time in eight years the printer is having problems and I'm pretty lost on how to approach this. A reply with what keywords to use to find a technician, what's to be expected, and how technicians generally charge for their services would be appreciated. 

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Oh, and I have OS Catalina. But my printer is connected with a USB cable and my laptop recognizes the printer and obviously makes prints... but could that be a contributing factor? 

[mannyfres79]

How long have you had this printer? It sounds like a dirty printer head that needs to be cleaned. Check videos online how to clean the print head.

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Thanks for the suggestion. The printer's about 8 years old. I did the head alignment, deep cleaning, and everything else I can possibly do as a non-inkjet-printer-expert. I did find an inkjet printer repair professional and got a quote for between $250 - $550 to replace parts and whatnot. Ended up getting a new printer instead.