Speed issues on the R8000 Nighthawk

So I recently purchased the R8000 Nighthawk X6 AC3200 - On day one since my bandwidth from my provider is 300 Mbps down and 300 Mbps up - I did get almost the same speed on my devices which are on Wifi on the 5ghz channel and near the router,

However next day onwards this dropped to 175Mbps up and down although in the admin panel under Dynamic QoS the speed test shows 297.88 Mbps 308.79 Mbps 

So I opened a support ticket and I was asked to install the following update R8000 Firmware Version 1.0.4.56 - Hot Fix (https://kb.netgear.com/000061990/R8000-Firmware-Version-1-0-4-56-Hot-Fix)

My question is "Will this resolve the speed issue i am having on my devices?" as doing a beta firmware update means I need to do a factory reset and redo all the settings again... I have backed up the settings but its still feels like a pain to do if this doesnt resolve my speed issue.

Any help would be most appreciated.. Thank you