I don't own a kindle but it looks like it's possible to download your highlights.

You could then bulk import them, possibly after some minor formatting manually or with a script

https://apps.ankiweb.net/docs/manual.html#importing-text-fil...

You would still have to go trough them and add cloze delitions.

If it's possible to add notes to your highlights you might be able to specify delitions there and then parse them.

I might actually do this myself for fun :)