I’ve been studying Japanese on and off for a while (cause I do tend to burn out, haha) and I’m still only halfway through N5, but I recommend using SRS in conjunction with other learning as, if you don’t, you’re never going to properly reinforce your learning. I don’t think it should be your primary source, but it is always good to mix things up a little. Especially if you get bored!
I bought the Genki I textbook and am working my way through that. Textbooks can be a slog, though, so I like to switch it up with various things. I watch a few YouTubers (CureDolly is a good one) and I highly recommend the Tadoku graded readers. I’m still only at level 1, but reading a book or two each night before I go to sleep really reinforces what I have been learning. Because my end goal is reading, I have bought a lot of books regarding particle, verb and adjective usage, plus a couple of dictionaries, Kanji and short story books. I don’t always use all of them, and some can be quite dry, but they are there if I need them.
It’s a slow journey for me, but I always get that hit of endorphins when I’m reading a book and recognise the kanji and understand the meaning of a sentence without having to look up every second word lol.