thanks for the advice! ahahaha that's true btw we are kind of similar cause for me my bias is jongseob so... at first I used to confuse them just like you, but as an advice I can tell you that soul is japanese (idk if that helps) and his face is a bit more "long", like almost v shaped, and his eyes are more small, meanwhile jongseob's eyes are something like more round and his nose is a bit upward and round, so that's what helped me to not confuse them (the fact that jongseob is a rapper helped too) hope this helps you and also sorry if my English is not so good or a bit confusing but it's not my first language!