What’s the best way for this? Learning vocab via Kanji, I mean. (Or any highly structured ways.)
I am thinking AnkiDroid, actually; but I haven’t truly use Anki + Sync for ages.
Also, I’d prefer to do least work possible, but sorting by Kanji is a licensed content. Any thought?
Kitsun.io is the best I think if you don’t mind paying. Features get regularly added and you can always ask the dev to get the features you want in it they aren’t already. It doesn’t have an app, but the website is mobile friendly.
What does kitsun.io think of 10k deck sorted by WaniKani levels, anyway?
I think there was this kind of Anki deck…
May be good to poke your head in the corresponding thread, where the dev is really active (I should have linked this before):
It might be a good idea to rename the thread to include the “vocab via kanji” part. From the title alone, it looks like you’re looking for a mobile app or something.
Anki syncing is seamless in my experience, so you would just have to find a good deck
I want exactly WaniKani deck, but that would be using licensed content, where people aren’t supposed to share.
Such deck isn’t existent in kitsun, only the BEYOND or INFINITY ones.
Also, I am open to non-Anki.
Huh? I’m pretty sure you can have private decks in Kitsun
The WK content is public now, and is visible even to non-account holders. Try going to https://www.wanikani.com/vocabulary/鰐蟹 while not signed in.
As long as you have the data in either anki deck or csv/txt/tsv format, you can import anything you want into Kitsun to use as a personal deck (just like anki). You don’t need to share any deck if you don’t want to 
Remember @prouleau has a script called Item Inspector that can CSV export… 
If someone tries to export to Kitsun with Item Inspector please let me know how it worked.