Sometimes I send dozens of emails that have the same text, only the recipient's name at the beginning changes. In thse cases, with good old Thunderbird I just create a template, open it, write the recipient's address, and send it. Swift and clean.

Proton doesn't have email templates. I'm lucky because I know of Thunderbird, but if I were just slightly less tech savvy that would be some stress you give me, Proton!

Note: Mailchimp and the like just don't feel privacy-oriented since they decided to block an account I used because the email was determine that it was encouraging criminal activities. It was an email that said "We'll have this new LinkedIn group for local craftsmen, join us if you like". So, yea, weapons made in clay are probably a thing in Mailchimp's AI's reasoning.