I’m not much of a musician, but I’ve used MilkyTracker for some chiptune work

A string has two ends

What level are your students (primary school, high school, technical college, university)?

You said it’s not a core skill, so what is their core skill? IT? Machinist? Electronics engineer?

C is an excellent “fundamentals” language that anyone with a software engineering and maybe computer science should have exposure too, but if their programming is purely practical (e.g. scripting for IT?) C is essentially irrelevant.

Javascript is very narrow in scope but if they’re web designers then it’s essential.

I’ll back the other commenters that if they need a language they can do useful things in (e.g. simple automations, calculations), Python is hard to pass over.

Three cueing peaked in the 90s.

School is the real world. It’s just their world, not yours. It’s where they spend a huge fraction of their day and year. School needs to be a livable place regardless of what comes after. “Preparation” if necessary at all, can come at the end or be taught explicitly instead of implicitly.