If anything, this post has only succeeded in making me even more anxious about all languages that aren't built on s-expressions...
S expressions without types make me nervous
The best way to get rid of that feeling is to work with them. Why not learn Common Lisp?
Because it is Lisp, you will be working solo anyway, and NIH-ing all your dependencies. So it is all good!
If it's all good, sounds like that's a reason to learn it. ;) But I have to push back some -- I mean you can work alone and build your own castles from scratch if that's your thing (I totally understand that appeal), as in any language, but you don't have to. There are libraries, some quite good, here's an incomplete collection: https://github.com/CodyReichert/awesome-cl It's also easy to interface with C libraries or Java libraries, there are options to interface with C++ and Python. There are also communal projects with more than one active developer if you wanted to work on such group things, and some companies here and there.