7 chords are dissonant. That’s why a (ii-)V7-I works. Dominant creates tension that gets resolved, or not. But the chord function is only one third of the pict

7 chords are dissonant. That’s why a (ii-)V7-I works. Dominant creates tension that gets resolved, or not. But the chord function is only one third of the picture. Dominant chords can have greater or lesser tension depending on which extensions are used. A closed voicing will sound more dissonant than an open one.