Author here, I work at IPinfo. some security-relevant highlights part of the post:

• The August 28 Virtualizor update attack used a forged-origin /24 inside Hetzner’s space. From what we saw, it was RPKI-valid because Hetzner’s ROA covered the /16 and allowed announcements down to /24, and no real /24 existed to compete with it.
• We also measured how common that setup is. In this case, of 855,217 RPKI-covered IPv4 routes, 138,698 (16.2%) have a ROA looser than the route announced and no more-specific route of their own filling the gap. For IPv6 it’s 20.9%. That’s roughly 18 million more-specifics someone could announce today and come out RPKI-valid and uncontested.
• Hosting providers also differ a lot: Contabo leaves 540 of 553 covered routes open, DigitalOcean 780 of 863, OVH 11.5%.
• Invalid routes are being dropped now: a typical valid route is seen by 596 vantage points, an invalid one by 2. So the remaining risk is routes that pass the check, not ones that fail it.
• There's also the fix in RFC 9319: leave maxLength unset, so a ROA only matches the block you actually announce.

Method is at the end of the post. Happy to answer questions