Yes I can create the certificates for each container, but that means multiple configurations of certbot. If I could use the same configuration to generate the different certificates then point the containers to the certificates, that would be far simpler.
As I said, I didn't expect it would but I live in hope...
Central SSL management is only possible if you have an ingress router like traefik that can handle everything, otherwise you will not be able to get the challenge right due to IP mismatches etc.