The process through which you parked the domains with Google entailed loading a file with the list of domains, after which each one would, in turn, be approved or denied. All 400+ domains were approved.
A few days later I received a cryptic message about unusual click activity on the domains and the Google account I had at the time was shut down immediately without recourse. I visited a few of the pages (not all 400, maybe a dozen) as they were approved to see what they put on them. Of course I did not click on anything. I might be accused of being stupid, but I am not an idiot. Besides, I pretty much knew the income would be a rounding error, maybe a few cups of coffee per year, maybe.
Well, nobody to call, text, email or send smoke signals to. Nothing.
That's when I decided I would never do business with Google. All I use from them is search. That's it. Nothing else. I can't trust them with anything that is business related and anything personally important.
Gmail? No way. I pay for Zoho mail for all the email accounts for my businesses and I am very happy about the product, the service and the isolation from a despotic company that can shut down your life in a microsecond.