Here's some content creators I recommend. They all make great educational content that help tons of Havoc players, as well as help out with the Demon Hunter discord. Shadarek also maintains the wowhead guide for Havoc, and has been a consistently high quality player and teacher, frequently pushing M+ title and raid leading a CE guild.
Voodoo
Youtube
Twitch
Discord
Shadarek
Youtube
Twitch
Jedith
Youtube
Twitch
Discord