It usually takes some time for an updated dependency to actually get shipped to users in a release, by which time there's a good chance the attack has been noticed.

Who is funding this security audit? Are folks supposed to volunteer their free time? It's a difficult coordination problem. The best folks have come up is to delay adopting new releases by a few days and hope your dependency is popular enough that a security firm audits it for you in that timespan. If you have enough money I suppose you can start employing llms to audit things for yourself.