Although I haven’t tried the Japanese course, I’m a bit skeptic about how really useful Duolingo is
Imabi is a good source, and you can complement it nicely with Tae Kim’s guide, as they have different ways to approach the same topics. Textbooks like Genki are expensive, but it’s what most people look into if they’re looking for a more structured approach.
For practice, Anki flashcards can be a good way to practice vocabulary and whatnot if used wisely, and there are many Discord servers where you can talk to other learners or to natives. I think you can get their links on Reddit. Also, let me know if I can help you with anything!
Please do keep consuming media you like to consolidate what you learn. It helps you remember what you learn and learn new things, and keeps motivation up.
I believe that after you reach a certain level where you get a gist of the language (i.e. you can understand pretty easily many sentences given that you know all the words and the grammar structures in it) you can dive into VNs armed with a dictionary and the Internet, and slowly work your way up to build your understanding and learn new words.
Just a little disclaimer, which tackles the reason people sometimes don’t recommend watching anime or whatnot to learn:
During all of this, you need to be mindful of the context of what you’re reading or listening to. Try to understand when a character is overusing some speech patterns, when they’re saying cheesy lines or when a word is too specific to be used in certain contexts. If you’re not sure, look it up on the internet or ask someone, but try not to mimic characters’ speech patterns unless you’re sure it’s standard. If you talk all the time like a hotheaded shonen main character or like a cute quirky anime gurl, you’ll just come out as silly.