Actually FreeBSD is great and for a modern OS better than linux in all ways but ecosystem and even there it’s fine. But also the design while it makes sense in some way kind of sucks, it’s messy.
This one is my favorite.
I actively avoid publishers and sellers who don't respect me as a consumer/reader. People need to start demanding better deals, or else we'll end up with monopolies that won't think twice about deleting books in your custody that you purchased from them.
In all seriousness, how has DRM not yet been recognized as the failure it is?
Build Your Own Lisp, by Daniel Holden. This is an often cited classic with a lot of precious concepts explained in detail. It can be read for free online. But this is an opportunity to reward them for it. (Yes, I do own a purchased copy).
Ansible for DevOps by Jeff Geerling. Already mentioned by the sibling commenter.
There a lot more on my wishlist. All of them are competitively priced at 10 to 15$ each.