jade of jade being, tinkle
琤 centers on the clear, ringing sound of jade pieces striking each other, producing a delicate tinkling noise. The meaning extends from the material (jade) to the characteristic sound it makes.
琤 combines 王 (jade) with 争, which likely contributes the sound. The character is used to describe the tinkling sound of jade, so the components suggest a phono-semantic structure where 争 hints at the pronunciation and 王 indicates the material.
The left side 王 (jade) and the right side 争 (conflict) can be imagined as two pieces of jade clashing together, producing a clear tinkling sound.
For ソウ, imagine the soft tinkling sound of jade as a gentle 'sou' whisper: sou -> ソウ, like the sound of wind chimes made of jade.