I wouldn't use cordially in signing off a letter or email.
Mostly I just put my name. Usually I have already written all I have wanted to say and ending with yours sincerely, faithfully or anything else seems a false statement to me, especially if a formal correspondence.
And now days most electronic devices recognise a 'sender' so even your name might not be necessary at the end of a message.
I still have the text book from high school giving all the
rules for letter writing, among other things. This
is called the "Complimentary Closing": Yours truly,
Affectionately yours, Sincerely yours, etc.
I have not used them for decades either.
