Find old privaterelay.appleid.com address.

I haven't changed anything in iCloud. I have TM backups. What happened is that I was prompted to login to Chat (as has happened before), but somehow I ended up signing in for a new account. Chat support says it can't access my old a/c (where my previous conversations are saved) without the privaterelay email that Safari (or whoever) assigned for the original a/c. iCloud only shows me the current hidden email address; so does Settings.

Thank you for taking the time to reply. I did that (and had, in fact, already tried that), but it only shows the current appleid.com address. Is there no other way to find the previous address that likely existed for my previous Chat account?