> If I want to learn a new language, does the discomfort need to relate to the language

Yes.

Comfort: Duolingo and similar. UX designed to make you feel proficient when in fact your are not, gamification, drag and drop words, point and click on things, streaks, leaderboards, etc.

Discomfort: write your own content, talk to people a bit before you are ready, seek content a bit too difficult for you, listen to a podcast many times to see how your understanding improves with each listening, deep dive onto a subject, shadowing exercises, etc.

In short: prefer harder and more efficient things even when easier and less efficient things are available.