Definitely listen to this. IP Warming is a very real problem and you have to send thousands of messages at a very gradual rate for most email gateways to 1) mark you as a proper email sender, and 2) classify you as a reputable one that isn't sending spam. Using a public/private cloud IP isn't enough, it should be a service already used for mail sending.
If you self host sending email and ignore using a service for outbound, make sure it isn't at home. ISPs often block SMTP traffic to keep people from spamming others from their home. A lot of IP blocklists also auto block home IPs so you may not ever get your messages delivered.
Make sure to set up SPF/DKIM/DMARC. At the very least SPF, DKIM if the platform supports it, and ideally all three or SPF+DMARC. It's not that hard to configure if you do it as you go instead of years down the line after you have a dozen services sending mail as your domain.
It's a discord reaction of the nerd emoji. Supposed to imply the snake is calling her a nerd for following what they heard