Sorry, I misread that one. I thought you meant self-hosted.
Just out of curiosity, have you tried or have heard of someone who tried? I mean nothing stops one from pointing a Domain to a Home ISP IP address and creating DKIM and SPF entries for that. I kind of doubt that Google can determine with high accuracy whether an IP is from a Consumer ISP or not, especially when it comes to small ISPs - which might be the most interesting, when already going so far... ;-)
There are dynamic IP DNS blocklists and they are usually pretty accurate. Also, usually, your reverse name is pretty telling with home ISPs. Sure, you might be lucky with a small ISP, but then, with a small ISP, chances are they wouldn't mind giving you "static" addresses anyway.
Though indeed it would be an interesting experiment how domain and IP reputation actually interact at large email providers.
I have a home mail server and GMail accepts mail from it no problem. Outlook tends to drop my mail in the recipient's Junk folder but I haven't encountered any outright rejection.
Just out of curiosity, have you tried or have heard of someone who tried? I mean nothing stops one from pointing a Domain to a Home ISP IP address and creating DKIM and SPF entries for that. I kind of doubt that Google can determine with high accuracy whether an IP is from a Consumer ISP or not, especially when it comes to small ISPs - which might be the most interesting, when already going so far... ;-)