"Quiet quitting" revisited -- ever get loud about being quiet?

I'm curious -- those of you (like me) who have withdrawn from extra work outside of your defined workload (e.g. no extra service or teaching), have you just shut up about it, or have any of you loudly drawn attention to it? How did it go?

I'm in a situation where I've been volunteer teaching a course for years, but I've learned the department doesn't care (even if the university does) so I don't plan to continue doing it -- I'm curious if I should let my chair know the reasons I'm not doing it anymore, or just shut up and recover some free time, and contribute to a general "decline" of offerings to the university.

As an FYI I'm a tenured assoc. prof at an R1, so my time is largely my own without consequences -- I was enjoying helping the students and university out with this course until my department decided to be shitty about teaching.