If they're hitting the outbound SMTP servers, there's no way (at least that I know of) to protect the IP/servers via obfuscation with a service like Cloudflare etc. Email deliverability relies heavily on the source IP of the sending SMTP for reputation and is going to be viewable in the headers of an email. Also changing IPs isn't a small task unless you're sitting on a load of good reputation IPs that are... - Source: Hacker News / over 2 years ago

Good Sales Emails - This website leans on the copy side of things, but still great imo. (One of my Favorites). Source: 12 months ago

Practice cold calling/objection handling along with well written sales emails. Being a smooth criminal on the phone/zoom is the most important skill in sales. To learn the basics, print out some mock cold calls online and run through them OUTLOUD (find a friend to role play w you if possible). For emails, here is a link to kindve get the idea https://goodsalesemails.com/. Source: almost 2 years ago

EXAMPLE: I found this example on GoodSalesEmails, an awesome resource created by u/r_pg101. It’s by a company called Swiftype. Look at how they sign off this cold email: “I would love the opportunity to share more of why you need Swiftype and how we can help your clients. How's Tuesday next week look for a 15 minute call?”. Source: about 2 years ago

With regards to the emailing thing, take some inspiration from here as well: https://goodsalesemails.com/. Source: about 3 years ago

Some time ago, I created Good Sales Emails to help other entrepreneurs out there getting inspired when doing cold outreach campaigns. Source: about 3 years ago