No they do just make it up. Non of the non-biblical traditions from any denomination can be traced back to the Apostles. It’s just made up.
That’s where cultists start from: the Trinity and the canon of the NT were “just made up”. Do you believe Paul when he commanded the Thessalonians to hold fast to the traditions they had received from him, whether by word of mouth or by letter? (2 Thess 2:15) Or was he just making that up?