To create a proper, compliant epub ebook, I use
Jutoh. Works a treat. I did the initial draft in Word, then imported that into Jutoh. It has styles and table of contents. Bit of a learning curve (as with any new program) but well worth it in terms of compliance with the epub standard. I used Kindle Create only to check the epub was compliant.
For publishing/sales, use:
-Draft2Digital.for most of the ebook publishing houses including Apple books (using Apple direct was too hard from an admin POV).
-Kindle Direct Publishing for Amazon
-Google Play Books for Google Play
You can set the DRM for each. Whether or not to is the $64,000 question. Are people really going to pirate your book? Will be cheap enough that people are happy to pay?