Fortunately, there are somewhat official Gumball comics, specifically 8 issues and 8 graphic novels, as well as some grab bag specials, all published by Boom Studios and available on Amazon. I guess it’d be good to start with the graphic novel series, as those are typically the longest comics: https://www.amazon.com/Megan-Brennan/dp/1608867447/ (160 pages long!)
A comprehensive list of all the Gumball comics can be found here: https://theamazingworldofgumball.fandom.com/wiki/The_Amazing_World_of_Gumball_(comic)
Good luck and best wishes! :)