WoW Slowing Down & Stuttering/Audio Crackling on Laptop

Hoping someone can help me out here.

I've bought a new mid range gaming laptop (HP Victus 15) that runs WoW at 30fps on high (around 7/8 on WoW's in game scale).

I actually have the graphics set relatively low for everything except my own spell visuals and character details (can't remember what the actual setting names are) to boost FPS and because I'm not overly bothered about the graphics.

So water, shadows, view distance etc. are turned down and other peoples spell visuals are limited as I'm not really bothered by them and am more interested in higher FPS/cooler laptop.

I have my laptop set to high performance when plugged in and on battery but as soon as I unplug my charger the game starts stuttering and the audio goes really crackly. This **only** affects WoW, other games are fine as is Spotify, Netflix etc.

The laptop comes with Omen Gaming Hub but I can't see anything in there that's throttling any settings.

Anyone have any ideas of what I can do to sort this as it's driving me nuts?