Yeah I did about two hours a day as well while I did WK and now its around four hours a day. Level 30 is definitely doable by the end of the year while getting a good foundation in grammar assuming youre decent at picking up stuff.
I started getting into reading Visual Novels around level 25-30 which aren’t books, but close enough. Guessing by your name, you may have an interest in them as well and I think they’re much more beginner friendly than books. Not saying all of them are easier (some are far harder than you would expect), but their advantage over a book is the ability to hook the text and run it through a parser. Long story short, this makes it super easy to look up words and saves time.
Another big part is how willing you are to bang your head against a wall. Failing and sucking is an integral part to teaching yourself japanese fast in my experience. This is my biggest problem with classrooms since they test you over stuff that they expect you to get a 90% or so on and move at a pace thats easy to follow. The fastest improvement comes when you’re truly challenging yourself to the point of even being mentally fatigued by the end of your studies.
When I jumped into visual novels, I really didn’t know the verb conjugations that leebo posted. I knew of them and had looked over them, but I hadn’t memorized them along with a ton of other very common grammar. My process was simple: read an incredibly long visual novel and look up everything I dont know. It was a pain in the ass and gave me headaches by the end of hour long sessions, but I learned a lot. I could have read simple texts, yes, but honestly I feel like I learned more this way than I ever did reading something easier like yotsubato. So long story short, if you wanna get through books at a decent pace, the first step is getting through books at a dogshit pace. There are alternative methods and I wont knock them, but thats my personal opinion and experience