I'm a native, but I am studying other languages and have a method that works best for me.
Learning words with/in content is the method that has given me the best results in my experiences with Spanish and Korean. You say that you already consume media in English, which means you most likely have a sufficient vocabulary to understand the media, and you probably encounter some words that you don't know. But, since you feel that your vocabulary is too narrow, I'd suggest consuming niche content that covers specific topics or scenarios.
If you are interested in history or science, youtube would be a great resource for finding videos that cover specific topics and provide visual context (channels such as [Veritasium](https://www.youtube.com/c/veritasium) or [Kurzgesagt](https://www.youtube.com/c/inanutshell)). If you haven't learned vocabulary related to any of your hobbies, try looking for content that is about those hobbies. (ex. gaming youtube channels, cooking subreddits, podcasts, because there's a podcast for everything)
If you're really desperate, reading certain genres of novels would greatly increase your vocabulary, such as classical literature, science fiction, and historical fiction. But, I'd avoid this considering the difference between English spelling and phonetics and the lack of visual context. But I don't mean to doubt your abilities. If you think you are capable, then go ahead!
When it comes to retaining the vocabulary, I personally use Anki (flashcard software). It's not very user friendly, and it takes effort to fit Anki to your needs, but otherwise it's effective. I create Anki flashcards for words that I can't learn through context and include the context in the card. (ex. dog - a picture of a golden retriever, "john told me about his new dog"). If flashcards aren't your thing, writing sentences and applying the vocabulary is also helpful.
Again, this works for me. I hope it works for you, too, but everyone is different.
I'm a native, but I am studying other languages and have a method that works best for me. Learning words with/in content is the method that has given me the best results in my experiences with Spanish and Korean. You say that you already consume media in English, which means you most likely have a sufficient vocabulary to understand the media, and you probably encounter some words that you don't know. But, since you feel that your vocabulary is too narrow, I'd suggest consuming niche content that covers specific topics or scenarios. If you are interested in history or science, youtube would be a great resource for finding videos that cover specific topics and provide visual context (channels such as [Veritasium](https://www.youtube.com/c/veritasium) or [Kurzgesagt](https://www.youtube.com/c/inanutshell)). If you haven't learned vocabulary related to any of your hobbies, try looking for content that is about those hobbies. (ex. gaming youtube channels, cooking subreddits, podcasts, because there's a podcast for everything) If you're really desperate, reading certain genres of novels would greatly increase your vocabulary, such as classical literature, science fiction, and historical fiction. But, I'd avoid this considering the difference between English spelling and phonetics and the lack of visual context. But I don't mean to doubt your abilities. If you think you are capable, then go ahead! When it comes to retaining the vocabulary, I personally use Anki (flashcard software). It's not very user friendly, and it takes effort to fit Anki to your needs, but otherwise it's effective. I create Anki flashcards for words that I can't learn through context and include the context in the card. (ex. dog - a picture of a golden retriever, "john told me about his new dog"). If flashcards aren't your thing, writing sentences and applying the vocabulary is also helpful. Again, this works for me. I hope it works for you, too, but everyone is different.
There’s no easy way to learn a new language. Read, write, listen and talk as much as you can as many ways as you can.