Gamified EdTech Platforms as Void Objects: Learning Algorithm Opacity, Engagement Over Outcomes, and Documented Harm — A Within-Domain Spearman Convergence

Twelve gamified educational technology platforms (Duolingo, Chegg, Course Hero, Byju's, IXL, and others) scored on O (learning algorithm transparency, engagement vs. learning metric disclosure), R (adaptive difficulty, streak recovery mechanics, notification engineering), and C (streak lock-in, social features, subscription friction). Spearman ρ between Void Index and documented harm: academic integrity violation rates, OECD learning outcome gaps, Huynh et al. streak anxiety data, Byju's FTC action. EU AI Act Annex III §3 (educational systems — high-risk).