Just to answer this part specifically and emphasise something that auruille said - beyond writing, this issue will get a lot better if you have exposure to kanji outside of the WaniKani environment. If your grammar isn’t yet at a level where you can read anything then I wouldn’t worry about this too much; you’ll get practice when you get practice.
If you do think you can start to read, then I’d take a look at getting some low-level graded readers or similar to give you a bit of exposure.
I might also recommend this font randomiser script, as it can help to reduce your dependence on the WaniKani font specifically.