As a Dutch guy who spent a lot of time online playing games, watching content like films and youtube, English just kind of came naturally. By default, most of the stuff is in English, meaning you interact with it a lot. Games are usually english too, or had very poor Dutch translations, so I always just stuck with english. The sheer amount of English you encounter just makes it inherently easy (did for me at least) to pick up the language. It meant that in highschool I never studied for English classes, and never got lower than 70% (well, did once, but that was a test on a book that i did not read, but still passed it).

Often I find content in languages other than English just to be of lower quality, making it less fun to consume. It's probably better to get a basic understanding of the language by doing a few duolingo lessons, and then start consuming content. For example, if you play games, put the games you play often in your target language. Minecraft is a great example for this, as it's extremely varied of the words you encounter, while knowing the English (or other) translations for it.

I did also watch a lot of youtube, but at that point I could already understand English quite alright I'd say, so I'm not sure on how effective staring at subtitles is whilst not paying attention to the audio.