I have a simple question, that I cannot seem to be able to find a definite answer to anywhere.

We have a productive environment with Python using aiosmtplib library to send emails automatically through Gmail’s SMTP Server. Our domain is setup on AWS Lightsail. Right now the python App is sending mails correctly but every few weeks our no-reply mail gets flagged and disabled for spamming.

If we setup the DKIM Records on Lightsail and configure the Authentication procedure on Gmail, without having the python app implement the DKIM signature, will this cause all emails sent from the python App without the DKIM signature to fail?

I am aware that I can implement the headers and signing process in aiosmtplib, but this is a production environment and we cannot simply disable mailing services while we configure and test DKIM. Besides we cannot test the signature and headers without enabled the Authentication on Gmail first, which is problematic for too many reasons.

If setting up DKIM actually causes all unsigned mails to fail: Is there a clear path to setup DKIM (and SPF) on productive enviroments without forcing a shutdown of current mailings?