How else can you change your email address in Steam if your email address is blocked or deleted?

Hello.

Since my friend and I want to play multiplayer, and his game is on Epic Games and mine is on Steam, he needs to link his Epic Games account to Steam. The problem is, once he links, he needs to access the confirmation link that was sent to him.

But now comes the biggest problem: The email address he used to register for his Steam account has long been blocked because he hasn't used it in a while. This means he can't even access his confirmation code.

And that's why I wanted to ask: How can someone change their email address on their Steam account if their old email address has long been blocked? So, they still have access to their Steam account. And no, they don't even have a phone number listed in their Steam account.