An FYI for the adventurous amongst you: beta testing of mod_md with support for multiple certificates per domain has started. This allows you to obtain RSA + ECSDA certificates and Apache will negotiate with the client about the one to use (which is mostly done by the SSL library). You can build this against an Apache httpd 2.4.41.
Monitoring and OCSP Stapling of
mod_md will pick up and handle these additional certificates also, of course.