I'd at the least throw away apps and learning games, in favour of books (especially those with audio samples available).
If the Duolingo Japanese course is anything like the Duolingo Russian course I did, there's no explanation for anything and they just throw sentences at you to translate. I think they only give actual information to the French/Spanish courses as that's what most users are looking for.
Well you see the exact issue with Duolinguo as pointed by others is that you feel you progressed for some months while in reality you didn't. If by the "characters" you mean hiragana and katakana both set can be learn to basic proficiency in a week (actually over a weekend for motivated people). If you mean kanji, the first set of 80 can be done quietly in a month (3 weeks in my case, when I was in high school, no tutor, no class, wikipedia only).
There are several ways of learning Kanji, each with their benefits and drawbacks, such as WaniKani, Remembering the Kanji, Kodansha Kanji Learner's Course, etc. Ultimately, Kanji are painful and time-intensive to learn, so none of these will be perfect, but you can maybe spend some initial time trying to find out which works best for you and then just stick with it.
Stay away from Duo. There's no structure to its teaching of Japanese, and it's not set up to let you intuit the grammar or structure either.
Duolingo isn't optimized for Japanese and it shows some major pain points especially around kanji and Japanese grammar.
There are a lot of more specialized Japanese learning apps if you need an app, and also many good textbooks and video lessons that are probably better than most apps.