Title says it all, I signed up with an incorrect email but GOG accepted it, is it possible to change it? For example, is it at all possible to migrate my account to a new email address?

You can change your email here: https://www.gog.com/account/settings/security

If it doesn't work please contact support.

Good day. I need login into my account where I have my games but i write in registration wrong email and now for number code is everytime in mail that I can't open because of using another person. Have this issue solution? Thanks

You need to open a new support ticket. Repeatedly telling the chatbot the suggestions weren't helpful should make it do that. When you do finally have a support ticket, it'll probably take weeks to get a response. To expedite matters, it would help if you include any proof that you own the other account, like a copy of an order receipt.