DKIM, DMARC, SPF, rDNS/PTR, EHLO... all correct and verified in the email "original source," BY GOOGLE. Still goes to SPAM folder because **** you, apparently. I hate Google.
One of the problems with self hosting is that a lot of IP addresses have historically been used for spam and still have a bad reputation. If you get assigned one of those IP addresses there's very little you can do about your mails going to spam.