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.
I've been hosting my e-mail for over 2 decades now, e-mail goes everywhere but gmail (despite working with them for years). They are doing it exactly so people stop doing it.