To be honest, the closest I have come to being published was as an Editor. And it was for a Western style graphic novel, not a manga. A friend of mine wrote and drew (actually analog painted) a graphic novel about World War II. He asked me to help edit the dialogue, and I ended up helping a little with the panel layouts also. He self-published it on Amazon, and he was happy with the process and with the products - both digital & printed. I should add: he’s a retired engineer, like me. And he was more focused on artistic expression than making money.