Just my experience with e-publishing.
If your document is in WORD, both Kindle and Kobo have a fairly easy process to move from WORD to their e-book formats. It might take 2–3 hours to go through the steps. But I have put up four books in both places, and it seems to be getting easier.
Unless you have a MAC computer, don’t bother with iTunes. I tried a couple of friends with MACs to help me out. There was a pretty big learning curve that they did not want to go through.
There are other e-book retailers. I cannot comment on how easy their processes are.
Last I heard, Amazon still has 50% of world e-book sales.
There are e-book brokers who will do everything for you, putting your book with 20 or more ebook retailers. But they want several thousand dollars.
Websites are pretty easy and cheap to build these days. I’ve got all four of my books available for a free read — they can buy later if they want.
But marketing is another matter. I’ve been on Medium for three years. I was able to move of few people to my website in the first year and read a little about my alternative governance. But in the last two years, maybe three partial readers from Medium. People don’t like my vision. But your kind of story should be attractive.
Hopefully, this has been some help.