I hate GMail and G Suite spam filtering. I am an freelance consultant, and a number of times I have seen my business email (hosted at FastMail) go to spam in a

I hate GMail and G Suite spam filtering. I am an freelance consultant, and a number of times I have seen my business email (hosted at FastMail) go to spam in a Google hosted mailbox. As a single consultant, I don't send a huge volume of mail because a number of my clients set me up with their internal email for business communication. The mail that I do send is invoices, and setting up contract signing; that sort of thing. The mails are always expected communication. I have SPF and DKIM configured and validated by FastMail. Mail somehow still goes to spam. I set up with google's postmaster tools, but it shows nothing because I don't send a big enough volume of emails for it to care. I set up dmarc to get reports when mail is delivered under my domain to a GMail or G Suite hosted address. Every single dmarc report (it's easy for me to keep on top of them because my mail volume is that low) is "spf: pass; dkim: pass". I really don't like that the only way to get this looked at is through publicly shaming Google like this; I have not seen any way I can talk to somebody at Google to solve the problem. FastMail support said they were unable to help me solve it either, suggesting I need to send mail into the Google garden and have the recipient click "not spam" until their filter learns.