cl-hamt

There's actually an implementation of the same HAMT data structure that Clojure uses available in QuickLisp and on GitHub: https://github.com/danshapero/cl-hamt/ Technically, since the hash-table implementation isn't specified in the CL standard an implementation could use a HAMT for the built-in hash tables, but I don't think any do.

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 men

There's also https://github.com/danshapero/cl-hamt/