The idea is to proxy only certain endpoints to the C2 server (change the default profile and make an entry for each route).
Register Account with njal.la and buy a similar sounding domain anonymously
Register Account with mailgun and subscribe to enable custom domains, then register your fresh domain there and make the required dns entries
Setup GoPhish Server on a EC2 instance, use mailgun smtp credentials to send mails
Then setup a good landing page, link the page in your email and have the page contain a download link for a document, exe etc., depending on your pretext.
Finally test your mail vs. a private address and if everything works out send it to the targets. Make sure the pretext contains calls to action and a sense of urgency (e.g. install this software to keep working remotely, fill this document to receive something etc.)