No sound on line out when headphones are plugged in

[gleaming bough]

So i have my speakers plugged into the motherboard's line out and the headphones are connected on my case's audio jack
the thing is that, with only the speakers connected it works fine and when I plug the headphones sound goes to the headphones, but when i select line out as the output there is no sound

forgot to mention i'm using pipewire and kde