If you have one of these, it’s possible that GitHub would honour it if you go via a lawyer.
Hope you manage to get it sorted but I have no idea how that would go down at this point. I’m sure at least one of them could claim they copied it off the other ones and then you’re shit out of luck.
I've seen people on Reddit writing things like, "Come on, what's the big deal? AI can write any code now." I disagree. There are hundreds of thousands of lines of code here, very complex code, which even AI wouldn't be able to write on the first try or in a single day. So this person stole this code from Photopea and built a product on top of it.
Use a trademark.
Something else is needed. If the code is basically open, then there is no technical protection. Remove tens of those repos - hundreds might appear.
I would imagine they all converge on common features and core implementation foundation