I’m not an expert on teaching teens. What I have done is content-based teaching of science, geography, and maths in English, and training and support of CLIL teachers – and that’s a lot easier than teaching English. The interesting lessons are often practical things, and mistakes in English are not even corrected!
Looking quickly for references for teaching teens, I found many coursebooks and online courses. I find the “interesting” themes are trivial and superficial – maybe I am too old! I don’t believe that these are much use in a Swiss environment, without British TV and pop culture.
I found https://www.teachingenglish.org.uk/article/keeping-teens-interested is well worth reading. Please comment with your ideas.