Judging from some of the experiences upthread, even that isn't enough. Billing messages from google themselves and gsuite-to-gsuite messages getting spammed.
Any source can have some fraction their messages treated as spam; I was just saying that if you take a random IP address and set it up as SMTP, you will have trouble getting any messages through, even if DKIM &c. are setup correctly.
Would Google still suspect my mail of being spam If I bring my own domain to Gsuite or rackspace (for instance) ?