If you really do want to start with something fairly bare bones for a CRUD app with SSR (server-side rendering of HTML), my user manager example should be fairly easy to follow.
It’s built with Ring, Compojure (routes), Selmer (HTML templates), Component (lifecycle management of resources), next.jdbc (database access).
It uses SQLite for normal operation, but any RDBMS could be used. It has tests and uses H2 in-memory as the test database.
It uses the Clojure CLI / deps.edn which I prefer over Leiningen (at work, we started with lein a decade ago because it was the only option, then switched to boot in 2015, and then to the new, official CLI tooling in 2018). I think it’s a lot simpler to work with than Leiningen (although Leiningen is “easier” to get started with).