Using my own netgear XR500 router which does allow 1gig, however i have only seen speeds over the weekend of around 500 download.
Your speeds are too low.
I have two XR500 routers - one connected to the ONT and which serves this PC, then another one upstairs connected to my home server and wireless points. I was getting around 730Mb down on the double-natted one upstairs on various testers.
Using the one downstairs (connected to the ONT) shows again around 730 from TBB:
https://www.thinkbroadband.com/speedtest/15930862268...
Google is similar, but Ookla shows pretty much 900:
https://www.speedtest.net/result/9660834128.png
I would say something's up in your case!
EDIT: This is with Cerberus, I regraded my connection earlier in the week as my FTTPoD contract had expired.
Edited by deleted (Thu 25-Jun-20 13:19:33)