"Should I learn how to read fluently, understand spoken speech, or speak fluently first? Is it a mix of two or more?" < If you're not studying for a test, it really just depends on your goals. To me personally, understanding spoken Japanese is by far the easiest, then it's speaking, and then reading. Those two can swap places depending on your learning environment / goals.
If you have Japanese friends and/or frequent language exchange communities, your conversational skills will improve very quickly.
If you like reading manga, books, articles, light novels, etc., you might want to lean into kanji and getting better at reading in general.
One combination I don't really thing is possible, is having good conversational skills, but not understanding spoken Japanese as well. I'd argue that understanding spoken Japanese is a prerequisite for developing conversational skills. I can't picture a fluent speaker who doesn't understand what people are saying to them. You develop conversational skills through conversation.
Anyway, the point is there's no right answer to your question. You have to figure it out for yourself. It's difficult to give you personalised advice when we know next to nothing about your goals and learning environment.
"It’s been 2.5 years since I’ve started learning Japanese, and all I can say is that I’m not satisfied with my progress" < Around N4-N3 seems very reasonable for 2.5 years, but that's just me. Not being satisfied with your progress is quite common, and very "human".
I'm almost never happy with my own progress, but at this point Japanese is so intertwined with my hobbies and everyday life, that the thought of "giving up" feels quite alien. I might take a break from my more "formal" / "structured" studies, but I'll still be following my favourite content creators, watching a copious amount of anime, reading manga, etc.
In fact, that's what I've been doing for the better part of almost 15 years. I tend to alternate between long (1-2 years) periods of consistent "formal" study, and equally long periods of casual immersion.
So if you feel like you need a long break, I think that's perfectly fine :) Although I'd recommend maintaining some level of casual immersion, if possible of course.
"I just can’t seem to get past my current level. It might be how I’m studying, it might be how often I’m changing my studying method, I have no idea." < I don't really know *how* you've been studying, or what "often changing studying methods" looks like for you, but I do know that progress can be gradual, to the point where it feels like you're stuck, even though you are actually making progress.
Assuming you're consistent and your study method is half-decent, you WILL make progress. 
I think comparison is what tends to kills motivation and breed unreasonable expectations. We have this habit of comparing ourselves to the very best, thinking that we're looking at the "average". There are also a lot of things you just don't know when looking at someone claiming they've "mastered" X language in Y time. They might not be anywhere near as good as they think/claim. They might have had a lot of prior experience that they've conveniently forgot to mention, etc.
Anyway, I don't want to spiral into a rant on how much I hate "language gurus" and fake polyglots...
As for suggestions... I think I'd need more information first. I'd just end up giving you general advice that probably won't be very helpful. I guess my usual advice is to incorporate more immersion (I think that's reasonable for low N3) into your routine, and generally just *using* the language more. You could even take a bit of a break from more structured studying while doing it.
You certainly won't learn faster (quite the opposite), but you'll (hopefully) recharge your motivation and eventually get back into studying.
I think that's all I can give you, the rest is up to you :)
PS: If you're ok with sharing a bit more about yourself and how you've been studying, we can probably give you better suggestions/advice 