You can use Google calendar to send recurring emails. G-Suite Calendar is of course available no cost. No HTML--so users will need to "copy and paste url into browser window". I use google url shortener and create a short cut phrase "https://goo.gl/" then paste in the unique alphanumeric string to follow the final forward slash, e.g., https://goo.gl/VBwLPJ takes you to Silviesrcs support solutions page.
Here's a five minute How to video to use Google Calendar to send recurring messages:
Thanks for sure,