I have heard recordings by Kenny G and researching this question found some samples of Dave Koz. They are not jazz musicians. They are "Easy Listening" pop performers.

Sidney Bechet was the greatest soprano saxophone jazz musician. He took New Orleans to Paris, there are still many saxophonists who follow his style. The best of those was Jacques Gauthe of New Orleans, who died a couple of years ago.

Most alto and tenor saxophonists played in more modern styles than I like. Frankie Trambauer was a great on the C-Melody and is best known for his work with Bix Beiderbeck.

Adrian Rollini was the greatest jazz bass saxophonist. He proved it could be done.

Kenny is great on his style (easy listening like said before) but Dave has way much more technical and diversificated content to "give back" to the audience like Kenny used to say. Koz is definitely an outstanding performer.
I play saxophone too and I have listened Kenny a lot in my life and I can say, what Kenny does today, he did in the 80´s, there was little to none advance in his playing or sound in almost 30 years.
Don´t get me wrong, I loved and still think Kenny´s sound is beautifull, but unfortunately, that´s all it is today, what is a real pitty, cause I thought, back in the 80´s when I was his greater fan in the world, my inspiration to take sax lessons - ask my parents!!!! - I even tried to make my hair look like his, thank god I have no pictures (we´re teenagers only once in our lives you know), I thought he would advance, evolve technically, but then, the years started to go by, I am not a teenager anymore and my musical taste and feelings changed and his sound, always the same, was left behind like a static cloud that persists in staying on his tiny position on a larger and beautifull sky that is known like "music".

I played sax for about 14 years in Jazz, and I can say, not Kenny G. He mostly plays scales and on a soprano.