I’ve used WaniKani for years (I’m on my 2nd time going through it all), and my biggest wish is still that the “visually similar kanji” feature was more thorough, and honestly, that they would be shown prominently when first learning a new kanji, not just when viewing that kanji’s page.
So many times I have to open a new tab because I’m like “Wait, how is this any different from that other one I’ve learned?”
Also, iNom, while this is not dealt with by WK officially, the unofficial WK script Niai Visually Similar Kanji does the job for me and could also help you.