Sonic Tech Support sent me an EERO router which recorded what appears to be a peak download speed of 806Mbps in a 24-hour period; that would be acceptable if it was fairly sustained but the vast majority of time I'm seeing just 150-250Mbps.
So sonic is blaming it on my computers rather than their service only because they saw the peak speed of 806Mbps at one particular time on one particular day. I tried to argue that's only a peak speed and it it is ~200Mbps most of the time and they should send someone out to check the line at the pole but to no avail.
I later learned how to use the EERO app to record speeds many times a day and it was consistently above 800Mbps. I was still getting ~200Mbps with on my computer connected directly to the ONT using various speed tests with various browsers. But then I downloaded the Ookla speedtest app to my computer and that consistently gives me over 800Mbps.
So I still have faith in Sonic!