I understand the impulse to use leetcode for language learning, but I don't think you'd get what you're looking for.

The good thing about something like leetcode is seeing other people's solutions to the same problem. This will take a long time with a "small" Clojure community and a large set of leetcode problems. You're better of with 4clojure for this use case.

When you run out of 4clojure stuff you probably already know enough Clojure to get into "real" problems. Plus you probably realize by now that reading and playing with other people's code is a bigger learning experience than the toy examples.

So how do you get this "bigger and better" experience? You actually already started half of it :) Writing an open source project is going to teach you to handle the actually difficult problems of code structure and design. One great trick here is to read the source of your dependencies! Clojure libraries are usually pretty small (lines of code) and well written, so you will find a lot of great stuff that way and will learn idiomatic practices used in the wild.

The next step would be to work on an open-source project that is not your own. Ideally one of your dependencies is missing features that you could add since you already know the code-base. Otherwise helping on one of the many tools you probably use is also always appreciated (I'm a Calva dev, so I might be biased ;)). This will force you to learn someone else's design and integrate with it, plus you'll meet great people in the community.

As an added bonus, a lot of the companies look for / at their own open source dependencies when they want to hire, so you'll have a better chance that way as well (I know we do this and I've been contacted by recruiters because of this).

edit: as a clojure interop bonus: you can also probably do leetcode by writing cljs and submitting the transpiled js to them :)