I was getting the same on Ethernet ( it’s not a Wi-Fi problem) The problem only occurred whilst I was watching the football on Amazon prime as soon as the game finished the speeds were back to 56mbps even though I was still watching prime
It’s makes no difference what other devices are connected the fact of the matter is my speed was 10% of what it should be whilst watching the game and then as soon as the game finished it was back to we’re it should have been same devices. Fire stick and iPhone X the only devices connected at that time
Once again it doesn’t matter what devices I have connected, if I run a speed test now it will give me good results just like it would before last nights game and after last nights game ! The issue happens during games which either points to a “traffic management” issue on VM side or I’m connected to the same node as every other sports fan in the neighbourhood!!!!!!