Currently my workflow if I do not understand a card and have already reviewed the tagged material is to search on google/reddit until I find a post related to that exact card.
Ankihub seems well positioned to provide a space to discuss underlying material on a card by just adding a “discussion” page for each note under “note details”. Moderation wouldn’t be hard as it would require Ankihub subscription and deck maintainers could select the most exhaustive explanation as the “right answer” if they want to crowdsource moderation a bit.
If you’re still trying to make Ankihub a freemium model, this could also work as a premium feature. It could be marketed as a source of information that goes beyond what is on the cards to augment learning, built by the ankihub premium community.
[if people like it and it works, you could monetize further by building an in-anki discussion viewer addon and/or by building a video library with professional explanations as <30 second video shorts on a per-card basis. The overhead for this could decrease dramatically if you just crowdsourced trusted creators and offer to pay them royalties for videos on a per-view basis.]