Looks like step-ca/step-cli [1] and mkcert [2] have been mentioned. Another related tool is XCA [3] - a gui tool to manage CAs and server/client TLS certificates. It takes off some of the tedium in using openssl cli directly. It also stores the certs and keys in an encrypted database. It doesn't solve the problem of getting the root CA certificate into the system store or of hosting the revocation list. I use XCA to create and store the root CA. Intermediate CAs signed with it are passed to other issuers like vault and step-issuer.
[1] https://smallstep.com/docs/step-ca/