Yes, as I said, at the beginning it is a little bit confusing.
In this way of playing 3-note chords, you have to forget to play full harmony chords, as we do for example in rocks/pop genres or country.

You have to imagine, you are playing in small combo group, let's ay a piano, a bass and the guitar.

The general harmony D7sus is given by the bass playing the root note, here the D note AND by the piano which will lay the 5th note, here the A note, within its chording play ; then the guitar will have more 'freedom', 'agility', call it as you want, to explore extended chords. Thus, you can get a very full and elaborate jazz sound.

See attached view for some examples.

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