Haven't done the above testing yet but just to add:
All devices are having a problem. So at least add a Samsung tablet and a Win 10 laptop. Also, all the wifi connected devices have the same problem. It's as if the internet goes to sleep for them and you have to wake it up by going to a website, waiting (or even timing out and trying again) and then you'll get sustained connection until you stop using for a bit.
On my main PC I use the internet heavily and swap between sites, etc, and don't have any problems. The PC where I initially found the problem will be streaming only while streaming. It is almost like if you're not requesting content from different sources at a high enough frequency, the router will put that connection to sleep, even if you are currently streaming content from a source.
All a bit weird.
