I thought I had some oddities and actually started a similar thread the other day with my connection https://forums.thinkbroadband.com/fibre/f/4657634-ex...
but compared to yours they're nothing.
My issues were that sometimes while browsing websites occasionally they'd not respond for a short while or need a refresh.
When running a ping from a wired device the ping is generally very good at around 7ms but then sometimes it would be much larger, going anywhere up to about 150ms.
I have a BT FTTP 150/30 connection which you can't monitor with the standard HH6 so I switched out for a Netgear R7800 which when monitored generally showed low latency but with some spikes when there is a light use on the connection but only at certain times.
Broadband latency with light background use
As I'm a bit of a geek and like tinkering I switched out the firmware for the Voxel version and now it's pretty good and the only times I see a problem are if you max out the connection and the QOS takes a couple of seconds to kick in and bring it back down.
Before 3pm on that graph was using the stock R7800 and after 3pm was with the Voxel firmware.
In your case I'd suggest disconnecting all devices, both wired and wireless for a short period of time and then see what the monitor reports.
If you still have packet loss then the next thing to try is a decent router, the model you have is rather cheap and you may find it just doesn't have the processing power needed.
The latency spikes are just when the connection or router are not able to respond quickly.
Alternatively I believe you can connect a PC directly to the ONT although you need to establish a PPPoE connection and give it all of the relevant details. Also bear in mind that your PC will be directly on the internet so should have a firewall.
If you find that the latency goes away then you know that the problem lies with the router, if not the the connection is at fault.
Edited by StuB (Thu 10-Sep-20 12:31:25)