> outside of very limited contexts, furigana

Sarcasm aside, I only take issue with this.

The context here is learning Japanese, ie a beginner. A typical way to do that with any language is to use the enormous wealth of resources aimed at either kids or learners. Including in this case many popular manga.

It's a context within which, of course, Furigana is widely available, as it's one of the ways Japanese themselves learn Kanji. And I would guess probably why it even exists, though I'm sure you could correct me on that.

Your view of Japanese seems to be from a very high level, encompassing its totality or close to it. At that level your assertions may be correct and relevant, but that's not where my comments, nor the OP with their post, are aiming.