Want to have separate audio outputs, one for headphones and other for speaker

I want to buy a audio splitter (since my laptop only has a single audio jack) but I think if I want to watch youtube videos with my headphones (yt vids output on my headphones) and spotify or yt music playing on my speakers, is a audio splitter the good option, because I feel it'll play the same source audio on both the devices, while I want to isolate the audio seperately on both the devices... Is there a workaround for this or some app I need to install to have it play separate on both devices.