Some feedback regarding your test site.
I've been having trouble getting good test results from speedtest.shaw.ca to the point it was showing me support options. I just signed up for the 300mbps plan and am on the Arris XB6 modem, but on the test was struggling to get 120+.
Turns out the problem appears to be with Chromium based browsers. Firefox is fine, iOS Safari is fine (330mbps). But in Chrome I've been unable to get good results (over 150) until I tried incognito. With incognito on, then I got 330mpbs every time.
I then reset Chrome, disabled all extensions. Re-ran the test to no avail. I downloaded the Brave browser, which is based on Chromium and it turns out to have the same problem on a clean install and also works better in incognito.
Other speed test sites look to be more consistent regardless of the browser, so it seems like a speedtest.shaw.ca problem. I am running Bitdefender and Malwarebytes, for what it's worth, though doubting they're an issue.
Anyways, thought I'd pass this on to support to see if anyone else can replicate the issue.