End-use inkjet printers want you to send them RGB data. Don't send CMYK color files to print on an end-user inkjet printer if you are expecting anything close accurate color.
End-use inkjets don't really understand what CMYK data is. So when you send them a CMYK file, it confuses them.... so they do the best they can. They convert the unknown color (CMYK) to something they do understand RGB. Then, for output, they convert that RGB to CcMmYyK for their internal inks. This results in multiple color conversions within the print driver itself and often results in color shifts.
Using Adobe RGB is also a possible mismatch. Most end-use inkjet manufactures build their machines for the "unknowning" or "uncaring" user. To this end, they often use the most common, standard color profile which is sRGB. For the average users printing from the internet, Word, or some other general application, sRGB is a perfect choice.
Because you know enough to change your profile to Adobe RGB, you may be introducing the color mismatch there. The printer has to convert your Adobe RGB profile to a profile it uses (sRGB). Any profile conversion "on-the-fly" by the print driver can result in undesired shifts. Working in sRGB will be far more universal overall and will probably result in prints which are more accurate where color is concerned.
I would suggest you work in sRGB rather than Adobe RGB. This is especially true if the goal is to provide files that can be printed by many users on their end-use printers.
If you find prints via sRGB are fairly color accurate but slightly darker, you could possibly adjust for that. You may be able to calibrate the printer itself. Calibrating the printer may help fix the darker prints without any need to adjust the actual artwork. I'm not familiar with Canon printers so I can't say for certain. (Random link about calibrating a printer)
Or, you could adjust the artwork to compensate for the slightly darker inks of the printer. But adjusting artwork would make your files more "localized", which it seem may not be the goal overall.