Input Lag - WoW Classic

[Lucky__Lew]

I'm playing WoW Classic in Desktop Mode with my Steam Deck Docked (ASUS gaming monitor ). It runs perfectly for about an hour, and then begins to lag, to the extent that's it's difficult to play.

I've got the graphics set to the absolute minimum and it still behaves the same. The Dock I'm using is https://www.amazon.co.uk/dp/B0BBRMT1MY?ref_=pe_27063361_487360311_302_E_DDE_dt_1.

USB Mouse and Keyboard are also plugged as well as my monitor (gold played HDMI).

Grateful for any advice and help. Thanks