When performing Speed Tests, using this site or others, in order to receive proper results especially with the Gigabit service it is vital to connect your device using an Ethernet Cable.
For those who are using Microsoft or Sony consoles should also be aware that these companies have reduced their bandwidth limits during this time due to higher traffic during the COVID-19 Pandemic.
The articles below discuss the reason behind their decision to do so.
At this time the proper channel to test your internet speed would be through a PC connected via Ethernet Cabling to your router.