I have titles on both Createspace and KDP. The ebooks sell more copies.
My objection to Kindle Direct Publishing is they make it seem as though getting your book into the KDP
Select program is "normal." Last time I had a look, you had to option OUT of Select, or be automatically included in it. That's good for Amazon, not the writer.
It's a crap choice for some writers and did not work for me when I tried it for 90 days. They claimed that with a 5 million dollar pool of money, writers could get a chunk of that change. Fine, but when 5 million writers sign up for it they get a buck each, no matter how many sales they made.
I lost sales, of course, and was not allowed to put my book on other venues like Nook, Books-a-Million, Kobo, and Smashwords. Kindle insists you have your digital book in one "store" only, Amazon. Ditto for Kindle Unlimited, which is also a bad deal for writers. I may have this wrong, but I understood Unlimited to pay writers based on pages read by the buyer. If the buyer reads a few pages, or none at all if they forget they've bought the book, the writer gets either a few pennies or zip.
Stick with KDP and you get paid 70% of the cover price and can have the book in multiple "stores."
Soon as I could, I got out of Select and my sales went up, and I made sales on the other venues.
https://justpublishingadvice.com/whats-the-difference-between-kdp-and-kdp-select/