I can’t speak for Japanese learning as I am just a beginner, but I did learn English at some point, didn’t I?
In my opinion, and what I expect will be the case for my learning process eventually, is that SRS will work most efficiently in the beginning for building a basic foundation of vocabulary with which to comprehend and learn grammar. Which is why I start reading Japanese in ABBC and Satori Reader now, as my next level.
I expect this phase to take at least a year, but at some point within this time I will start writing a diary/journal. Back in the day when learning English I used live-journal, but mostly stuck to real paper and writing by hand. Nowadays I’d consider starting a thread in the campfire and just type, as to invite people to correct my writing where necessary and perhaps start a conversation with me - all in Japanese.
The thing is that learning a language through reading alone will only get you so far. There is a lot of neurology going on only triggered when you take the step towards expressing yourself. Daily conversation would be even better than a journal for that stage of your learning. For English, I immersed into English speaking forums, or at some point found internet friends to chat with. I can’t tell you where to find this for Japanese, but maybe let’s consider this stage 4 of our learning, even after expressing yourself in logs and learning environments such as this forum?
IMO, the best approach to learning expressions and vocabs at some point is to write a private Japanese journal with real sentences, where you report what you read/learned about, what stuck the most to your memory, what you enjoyed the most; or go ahead and write a plain diary, what did you do today, what’s on your mind? Just write what you will, once the habit formed you’ll begin to use the new words you’ve just learned, and that will work ton times better than SRS.
But writing is my kind of drug, and I know it isn’t comfortable for everyone. Still I believe it is a powerful tool to get you on the level of writing/speaking Japanese, and unless you got fluent speakers at hand I’m afraid we’re all stuck to the screen, and that means typing skills.
Point of note: Don’t be afraid of making mistakes during that time. It’s important to familiarize yourself with your current understanding of Japanese and “solidify” what you think is the way of Japanese speaking. It takes courage, but there is no other way to identify and eradicate misconceptions of the language - which might be the invisible cause for some expressions and vocabs refusing to stick, btw.