If you're learning LISP languages, I'd recommend taking a look at these dialects:
It's great to see someone else learn LISP languages! I've found them to be both readable and useful, while most languages struggle to balance the two.
This is a pretty cool project of yours! If you're really into writing and using LISP, I'd recommend trying out GNU Emacs (assuming you haven't given it a shot already).
I switched from NeoViM myself, and I found that maintaining an init.el file to be much easier than an init.lua or an init.vim.
Of course, I don't dislike NeoViM. I think it's a great editor with a bright future. I moved because I wanted a GUI editor, as well as a stable release cycle. I stuck around because I found ELisp both easy to read and write.
I'm a hobbyist programmer, but I still think I can answer your questions.
Question 1
When a library is written in another language, it's most likely done to increase efficiency. For example, many libraries in Python are written in C, as C is a very performant programming language. Python, however, is slow but easy to write, unlike C.
A programmer would only be stressed about an external component if it were unmaintained. This is primarily for security reasons, as vulnerabilities in the library could be found and exploited. It being in a language the programmer doesn't know just makes them incapable of solving the issue themselves, which could be stressful to some programmers.
Question 2
This would never happen, as content isn't stored in the back-end. All content is stored on the production server (the one that viewers would interact with). This is especially true if the content is copyrighted. The most popular way to add content without developers needing to update the software is to use the metadata found in the file(s). For example, metadata can include the content's title, author(s), length, which season an episode is in (for TV shows), and much more.
The usage of "trigger" in a programming language wouldn't cause any anxiety. This is because of the context the word is used, in this case a log generated by the program. They'd know that the word "trigger" is being used to activate something (ex: X triggered Y to occur). Therefore, the programmer would be fine.
If you need me to clear anything up, just ask!