Technical SEO engineer to FIX mass "Crawled — currently not indexed"

I run ThreatCluster (threatcluster.io), a cyber security intelligence platform made up of: ~1,200 sitemap URLs of programmatic threat "cluster" pages and entity hubs (threat actors, CVEs, industries), genuinely unique structured content, updated daily. The problem: Google crawls the site and refuses to index it. Months of "Crawled — currently not indexed" across the corpus. Only the homepage is indexed. I have personally found and fixed a long list of real technical causes (below) and it is STILL not indexing at the rate a corpus like this should. I don't want a report. I don't want a strategy deck. I want someone who has fixed exactly this before, will find the remaining blocker(s), and will drive the fix until the indexed-page count moves. Already found and fixed by me: - Full SSR on cluster + entity pages (server/client render byte-identical; 390KB pages down to 99KB) - Inline-JS bloat externalised, content-to-boilerplate ratio fixed - CSS-defer bug (blank rendered screenshots for Googlebot) - Slug/title churn eliminated (frozen at first publish, old slugs 301) - Sitemap rebuilt, ghost pages gated, ~1,200 clean URLs - Entity pages thickened to 770+ words of server-rendered body - noindex/robots hygiene, footer link mesh, entity cross-linking - GSC resubmissions after each fix The job: 1. Find the actual remaining blocker(s). Not hypotheses, verified causes,demonstrated with GSC data, logs, or rendered output. 2. Specify or implement the fix. I'll pair with you on anything code-side; nothing waits more than a day. 3. Verify recovery and iterate until indexed pages move meaningfully. If your conclusion after real investigation is that the remaining issue is page quality or authority rather than technical, prove it the same way, with evidence, and tell me exactly what changes.