Regarding the ability to issue multiple domains, read this: https://github.com/oocx/acme.net/issues/5 . According to the final comment, one of these should work (I’m not quite sure which, it depends on the parsing code):
Finally, I’d like to point out that the ACME client you are using is unmaintained and uses the deprecated ACME v1 protocol.
ACME v1 is deprecated and is in the process of being removed: End of Life Plan for ACMEv1 . I recommend finding a more up-to-date tutorial that uses an ACME v2/RFC8555 client.