How to implement a one-time mailing from corporate mail?

Question

Mail server

Good afternoon. You need to send a letter from google corporate mail to a database of 800 recipients. The problem is that in each letter you need to indicate the name of the recipient's company, that is, each letter must be unique, and you don’t really want to do this manually. I use node.js and I know about nodemailer, but as I understand it, for such purposes you need to use an smtp server, which is not there) Gmail is also not an option through the transporter, since I don’t want to get into spam. I tried to do it through mailing services, but they refuse everywhere, since the database is collected from an open source and it’s impossible to prove that I’m not going to engage in spam. Is there a way to implement this automatically, and with minimal risk of getting into spam? And if you use nodemailer, then how and what smtp server to use?