No sound in headphones on Asus Rog Strix Z590-I Gaming Wifi (Realtek ALC4080 audio)

I installed 21.04 (alongside Win10) in order to get the wifi working (updates set to the latest as well), and it works beautifully otherwise; though it does take long to boot up.

The headset (3.5 mm jack) is detected, but when selected, the external speakers play instead, with no sound in the headset. The external 5.1 speakers are otherwise detected correctly. All other drivers are fine, including audio via HDMI and Display Port.

My issue appears to be similar to this one: Unable to play sound via headphones in my Asus Rog laptop

Grateful for any help. Thanks!