You might want to see if Speedtest also gives you the same results. What is the make and model of your router? If there's a router that is an intermediary to the ISP and your PC, might want to see if it has any firmware updates pending. Following that, check and see what BIOS version you're on for your motherboard. Cross-reference that with the BIOS version found on your motherboard's support site. If you have updates pending, gradually work your way up to the latest.
Also, which version of Windows 10(assuming you're on it) are you on? At the time of writing, we're on version 20H2. You might want to reinstall your NIC drivers if your OS is up to date.