just keep in mind that you help someone to pass 2fa account verification.
you have no info about the site/account nor OP but the site operator has now your phone number.
you might become complice of whatever the OP is up to with the site.
the only traceable link will be your phone number (and ID if you're german), enjoy consequences.
That's exactly my thought about all of this, anyway, people need to decide for themselves if they want to take the risk or not.
As they say: when it's too good to be true, it most likely is