Thank you for your quick reply! It was extremely helpful.
I have added the 1-line fix to map your from_name field to SendGrid's API. I submitted a PR to the nodebb-plugin-emailer-sendgrid GitHub repo, so that hopefully others can benefit too. This is the first time I have submitted a PR to an open source project, so I hope I did the procedure correctly. 🙂
The 1-line fix works on our installation, and I am now receiving emails which have a proper From name!