I originally learned how to speak and understand Japanese completely on my own (and unintentionally, ironically), and later learned to read and write once I entered university. As a result, oral/aural communication is my strong point. It was priceless to have vocabulary and grammatical structures already in my working memory to match the new content I learned in composition and reading comprehension courses, and my skill levels have evened out over time (although I still prefer speaking/using Japanese). Exposure to media, such as TV shows, podcasts, and music was the most effective way for me to gain language input, and although I never had any chances to speak Japanese in that first year or so, everything I heard and was thinking about in Japanese stayed with me. I didn't know I'd learned to use and understand Japanese until the first time I had a chance to use it with a family friend, and I realized that I'd picked it up from that consistent exposure and internal processing of how I saw the language working in shows, etc. As of now, I have my N2 and I'm finishing N1 prep, and I've studied Japanese for around 6 years. I'm about to finish a graduate program specializing in Japanese translation, and I work at the same level as classmates who have studied Japanese for 13+ years. So, how you study and how long you've studied won't dictate your potential for success, as long as you push to get to the right resources for your personal language learning journey!

I've been able to make progress in fluency in the same way with Mandarin Chinese and Korean. So I would definitely say that it was invaluable for me to learn how to speak and understand Japanese first before reading and writing. I do have friends and students who have learned the other way around, and from what I can tell, it seems to be more difficult to try to match up the pronunciations and grammatical structures retroactively. I think it might be overwhelming to try to piece everything together in your head if you're not actively trying to produce language and focusing solely on language input, although I imagine learning to read, write, speak, and listen to Japanese all at the same time would be overwhelming as well.

Of course, everyone's learning style and preferences are different. I'm an aural learner and a classically-trained musician, so it makes sense that my aural memory would have been a major factor in allowing me to learn the way I did. If OP is more of a visual learner, learning how to read and write first might be an option. But, even if OP feels like they can't freely practice Japanese out loud, they could say it in their head or find a safe space where they can practice.

Wishing OP all the best with this journey!