If you're using keychain all you have to do to sign in is use the username you have on keychain so yes I'm totally lost. I can't even grasp how there can be a username issue I don't know how it's possible on Hive/Peakmonsters ... I kid you not I am confused. Maybe @asgarth can explain how this is even possible.

You have an account you have tokens or cards in it. You use a system like keychain to sign in on peakd or peakmonsters or splinterlands it's all the same account.

I have never heard of the username being different between the login method and the site... whatever is on the site IS THE USERNAME and so that's what you have to sign in with. You will need the keys to THAT username.

Do you have someone that gets your issue maybe they can explain it to me in terms I may understand better. Maybe there is a bug somewhere... I just don't understand.