The problem you'll almost immediately run into is that modern computers typically use digital video streams rather than analog streams. You'd need to use VGA for the audio part (and that's making a lot of assumptions about the ability to send arbitrary stuff on it, I'm not exactly sure these days), and I'm not sure what readily available component could even be used for the video part.
I meant in the sense of getting one of those old 3.5mm-r/w rca adapters and plugging it into a modern thinkpad, phone or macbook, I’d assume anything taking digital signal by principal only wants frames of/approaching perfection