For books only available through Amazon my workflow used to be buying it, downloading it with their desktop app, importing into Calibre, converting to epub and stripping DRM, then pushing it onto my Kobo. They broke that a while ago by making their DRM even worse, so now I just pirate those books.
Books have got to be the least expensive form of entertainment out there. The value to cost ratio is incredible. Consider buying books to support authors and publishers. If you can't afford it, then libraries are nice too. I personally know people who pirate books, but pay hundreds of dollars a year for streaming services or battle pass type video games. It blows my mind. Books are so cheap people! I recently bought…
I have one that's been around since I was a kid, and I love taking the family there. Everybody picks a book, and it might cost anywhere from $80-120 (I've got a good sized family), but these days that's about what it would cost to go to a movie. And since you have a physical book, you can swap when you're done.
We also started celebrating Jolabokaflod a few years back, which is an Icelandic post-war tradition of giving books as gifts on Christmas Eve and reading them. This is a lot of fun, and it's a great excuse to hit the book store.