I agree with GP about refraining from "best practices" type advice -- at most leave it as "I prefer doing it this way". (Example: There was no mention of qlot for a form of version pinning, which would be considered a "best" or at least "standard" practice in other ecosystems, but while I use it I'm not going to insist other Lispers I don't work with do so too. They can keep doing things how they like. Common Lisp is not for the strongly opinionated.)
Apart from that though I do think it's useful to have the occasional new posts showcasing rebuttals to a few "myths" that won't die, so I appreciated your post. Some gifs of editor interactivity (like in https://malisper.me/debugging-lisp-part-1-recompilation/) would make it better. Though ironically (one myth has been "it has no libraries") perhaps some people might be turned off by the mention of so many libraries ("ok such-and-such is there after all but I have to type a quickload, why can't it come without any work?" -- programmers are often lazy in the worst ways). Before using every utility library under the sun and then some, I'd encourage people to get to know the base language... It's typically quite sufficient for many tasks. But hey, libraries are cool too.
Two other persistent data structure libs that came up in a thread the other day (though fset seems to be the most popular): https://github.com/danshapero/cl-hamt/ and https://github.com/ndantam/sycamore