I bought a Kobo for the same reason but when it came to buying books, none of the books I wanted to buy were on Kobo's store.
Even if I wanted to join, Kindle Unlimited is not offered here. I can't even buy the eBook from Amazon.
[1] https://www.amazon.com/gp/product/B00OZ4NMHU
[2] https://www.amazon.com/Anyone-Builds-Everyone-Dies-Superhuma...
[1]: https://www.kobo.com/ww/en/ebook/if-anyone-builds-it-everyon...
But I wonder if the reason for that little hoop was because of Kindle Unlimited.