Raw LLM Responses

I mean, im drawing chacthers for people in an art community who want their heroes in a better style. I don't want to charge them, but i did watermark my art. Im 17 and a lot of the art i make for others im kinda torn about because on one hand i want to keep drawing for them because a lot of them are my age, younger, or in some cases maybe an actual father with thier own kid. It feels so good knowing people love or like your art style enough to come to you directly or go to your instgram and support you, you know. But i had a run in one younger kid he was about 14, and he took one of my drawings and put it into Chatgpt and tried to claim it as his own. The craziest thing is he didnt even bother to switch it up, he just kept my logo that was in the bottom right corner, kept the pose (even though Chatgpt messed up on the hands and arms and overall body in some areas.) And i confronted him about it, and he was being kind on the surface im assuming to not make me upset and said he'd take it down. A couple of days later, it's still there, i even tried to get it taken down by youtube, but i can't, and i don't know where to go from here. Its kinda made me a little more hesitant when posting on YouTube atleast because im not as big as these other guys so i dont have the help i would like to get these things shut down from my area. It just sucks so much ass when you put all this time into something, and someone even a kid just puts it through AI, claims it as their own, and gets respected or praised for it. Sorry for the rant, and i know im late, so no one will probably see this, but if any of you have a solution to this issue, please help me out. Thank you, and i hope ya'll have an amazing day.