Mighty Jack and Zita the Spacegirl by Ben Hatke is a middle grade graphic novel (my kid enjoyed it at 5-6 years old, but I think the titular Jack is at least 12 yo in the book and I fully enjoyed the story as an adult).
Actually, we’re reading the collected works of Ben Hatke, because he easter-eggs characters from all of his books in his other books, and once we read one (I think we started with Julia’s House for Lost Creatures), the kiddo wants to read them all and figure out why the dragon in Julia looks familiar (it’s a hero in Mighty Jack, and makes a cameo as a baby in Nobody Likes a Goblin). Ben Hatke is one of my inspirations, too, as an artist and a storyteller. His picture books are really lovely pen, ink, and watercolor (what I love to make) and his graphic novels are bold, energetic, and fun.
Mighty Jack and Zita the Spacegirl is a mashup sequel to both the… you guessed it, Mighty Jack AND Zita the Spacegirl books. The Jack stories are a little bit older target audience than Zita (I’d say solidly middle-grade, with a maybe 13 year old protagonist, vs Zita who we meet at a younger age and worked for my kid at 5 years old). It’s a retelling of Jack and the Beanstalk… loosely… in that there’s a really awesome garden that opens up a portal to other worlds and there are kids climbing on beanstalks and eventually the adventure saves the family home. Do you like magical gardens? YEAH! Start with MIGHTY JACK and go from there. Prefer space adventures and maybe have a younger kid? Start with ZITA THE SPACEGIRL, a space-portal adventure about saving your friends and making new ones on the way, with lots of cute and/or creepy many-worlds characters. Either way, get all three of the books in the series you’re starting, because you will surely want to keep reading.