Ask HN: How to (partially) automate repetitive emails?

Hi HN, I write a lot of the same emails over and over again (macOS and iOS). What are your tips to automate or speed up this process? On one hand, I want my emails to have my personalized writing style but on the other want to automate as much as I can. My best solution so far is a shortcut (Shortcuts app) where I select the greeting, opening line etc., but one can imagine this gets repetitive after a while. Any way to mix and randomize things up a bit?