Monitoring Expiry Date of Root and Intermediate CAs

Hey there,
I am currently looking into options for monitoring Root and Intermedia CAs stored in Vault. More specifically, I would like to export the Expiry Date of all CAs, store them as metrics in Prometheus, and then configure alerts so that I would be alerted if one is about to expire.

However, I did not find a way to export the required information from vault. The built-in metrics endpoint (/v1/sys/metrics?format=prometheus) does not seem to provide it. Is there a recommended way on how to handle such a use-case?