I feel Ya - but it should not sadden you that you are not very good at something that you haven’t practiced.
WARNING !! SPORTING ANALOGY …
If I practice shooting jump shots 6 hours a day and nothing else, I shouldn’t be surprised when my dribbling skills don’t improve. Learning a language, like any skill, has various sub-skills which need to be trained. Reading kanji is just one of those sub-skills in learning Japanese, just like jump-shots are one aspect of basketball proficiency.
With that in mind, be aware that in the same way being awesome at shooting jump-shots wouldn’t necessarily make me a awesome at basketball - been a kanji master won’t make you good at Japanese.
Wanikani trains you specifically to be able to read Kanji, and recall readings when provided with visual cues. Recall is a different skill, that requires other learning methods.
I have in the past had a habit of beating myself up for not being able to understand something in Japanese - but when I step back and think about it, generally the reason i don’t understand is because I haven’t learnt the words / grammar / sentence structure, or haven’t done enough listening comprehension practice ect - so why should I understand it !
back to recall - I have actually noticed the longer I use Wanikani, the more I can recall words without the need for the visual cues. Not sure if that is my brain adapting? I hope so!!
Don’t get disheartened - learning a language is hard, but you’re doing it !
ps - that was a long ramble, and it is also quite late here. So apologies if it made no sense.