The link below might be of some help. Seems there's a couple of threads going on.
A possible answer has been suggested by someone. Waiting to confirm my side by that might be a little way off. Same problem as found in this thread.
I'm beginning to think it's the HH2 that is not up to the job.
Most who change out to a decent specification Router seem to get a result.
Watching with interest. 😉
I have also recently upgraded from the 500 package and so far extremely disappointed with the upgrade I've test speeds with both ethernet and wifi and bare in mind my laptops hardware is also running NVME up to 3gbps read and 1.8gbps write speed so i shouldn't be limited via storage either my download is very IN-consistently up and down from as little as 280 to 460. generally likes to hover around 360- 400 though with an odd spike up to 600 maybe once every few days. upload is generally solid at 119 constant. I'm fully aware the smart hub 2 has limited capabilitys with wifi using old out dated wifi 5 (2years old) however with my devices they should still be at least putting out at least around 600 commonly. Bt fttp team are useless at diagnosing and just say the line is showing 1010 which im calling rubbish on that! and sometimes they'd do speed tests on their end saying its around 700 annoyingly they would do a test when i say im doing one over the phone. the frustration is really annoying me ive already tried a new router which initially was even worse!