I did change the configuration because I added new domains to the existing certificate. Therefore, I had to install these new domains by adding something to the webserver config file.
I assume there is no certbot command I can run in order to check if automated renewal is on. Is that right?
But you requested a new certificate with certbot, right? If so, you put other/new webroots on the command line. And that should have also been saved into the renewal configuration file.
That is incorrect: you can use --dry-run (possibly needs --force-renewal too if it complains about "Certificate not up for renewal" because the installed certificate is too recent.) to simulate renewal: certbot renew --dry-run
In light of this and what you previously said, the certificate should automatically renew before expiry for all the domains it includes. Is that correct?