Regarding a favorite author

I was going through my Goodreads shelves today and I noticed the "add to favorite authors" option under the author follow button. So I go through my library (almost 5000 books, over 1500 read) and and try and find authors to add to this list. It isn't too hard since I have a shelf already dedicated to my favorite authors.

This is when I realize that there are a lot of authors who are my "favorite" but only because they have written or currently writing a series that I follow. I haven't read any of their other books (although I intend to) but it is only because of these specific series that I chose them to be a favorite author.

My question for discussion is...

What are the attributes that an author should/would have that would qualify them for "favorite author", and do you have to read more than one of their series or books to consider them a favorite?

I seem to have mixed up a favorite book, or a favorite series with a favorite author.

To me, a favorite author is one where if you see that they published a new book, you immediately get it and read it. I have authors who always publish on Kindle Unlimited, but I will buy the book instead of borrowing it.

There are a list of authors I stalk on Amazon or Goodreads in hopes of a new book to a favorite series or just a new book. There are pre-order no questions asked and authors and "mark the calendar because their Christmas Novella drops" authors.

There are authors whom I contemplate sending Christmas cards to because their books were just that good.

So, should I add the authors whom I have only liked a few books or a single series out of a larger collection?