I did the exact same thing with Duolingo but for German, but unlike you I didn't have any background with it so a literal clean slate.
Consumed German content as well - Movies, Shows.
And honestly, The actual German is way more tougher and different than what I got used to on Duolingo.
I still can't speak it, but I do know so many words that I can distinctly distinguish from a running sentence, but still can't form proper sentences, but hoping to add more elements in German learning other than Duolingo to fill the gap.
Do you think Children's book in the language might be a helpful addition in learning new language? As they are literally focused on getting children's hands-on with the language.
Thanks for sharing this amazing article and your insights though!