And it will mysteriously _stop_ being able to send mail to Google despite you doing everything right, because of whatever nonsense they use to determine reputation.
I am curious as to your experience with this.
Over the years, I have administered a few dozen small to medium domains (depending on the domain 10s to 10,000s emails per month) and the only thing that has ever affected delivery is the reputation of the sending IP address of the mail server (and ensuring DKIM/SPF alignment in more recent years).