I was happy to read some comments here reinforcing the experience I had - that immersion is absolutely necessary. For the sake of anyone who might ever be interested, and because today marks literally one year since I began doggedly learning Danish, here is how I get immersion while being thousands of kilometers away from a community of speakers (currently live in Brazil, before that Switzerland).

- The system language in my cell phone is Danish

- I started with Duolingo every day, but then after some 3 months or so it wasn't so fun/effective anymore.

- I read Danish news every day. Most often just the first two paragraphs is enough, but I make a point of understanding everything. Whatever is first on the webpage and is non-trivial. I know more about Danish handball than I ever thought I would.

- I found some Danish bands that I really like and I listen to them very frequently. For now I don't actively try and translate all the lyrics, since this is my "relax in Danish time", but I have noticed that I can pick up more and more - only then, I go and confirm to see if this is true or to learn what it actually is

- I read reddit posts in Danish (including on jokes) and I often try to write some responses myself. I am still ramping this last part up, but my procedure is: I first write in whatever flows: true Danish, broken Danish, a mix of Danish and German. Then before posting I ask ChatGPT to correct to C2 Danish and explain every little correction. I usually learn a lot doing this.

- I read LinkedIn posts in Danish, wikipedia in Danish when I'm searching for a new topic, and asking ChatGPT for responses in Danish when I have the time to read it through.

- I am also now increasingly exploring using Danish dictation on my computer, but this is still very much work in progress.

- Plenty of podcasts as time allows (I don't drive to work)

- Movies, first with subtitles in English and then in Danish

At this point, I feel that I can:

- understand a good enough portion of what is said in movies and songs to make me proud and motivated, although Danish pronunciation is notoriously difficult for the non-initiated and of course I am still a beginner

- understand written texts where the main difficulty is finding vocabulary rather than picking up the grammar

- I can actually understand some written Norwegian and Swedish, which is a pretty cool plus!