You have certainly had a time of it, Karina. And you have my respect for your resilience and following your passion for writing.
I wrote the article (my tuppence-worth) with another writer in mind. He's a bit sullen about his lack of sales and I hoped he would take heed. If he did, he would get at least one more sale.
I'm sorry you found my post discouraging. I had the opposite in mind. And I certainly have never told anyone their labour is worthless. I don't say that. Anywhere. I say self-published authors deserve their reward.
And I point out the KDP pricing support. Amazon looked at the historic data and gave us the figures. I was hoping writers would find this useful.
I had a look at your books on Amazon. I hoep your notebooks are doing well for you (I presume you are also selling these elsewhere?)
If your book isn't selling does my advice not make sense?