As you have said, first check the wiring, to make sure that red terminals on the amp are wired to red terminals on the speakers.

If that is so, see what happens when you switch speakers from left to right - easily done at the amp end.

If that still does not give a clue, the next step is to borrow another speaker and replace one of yours with it and see what happens.

Do i need a thicker wiring? Or wiring with a diffrent gauge

What’s your approximate length of the speaker wire to the speakers and what is the gauge?

The smallest gauge. And i know that we are in the new millenium, my uncle had an old component sansui with amplifiers bigger that a cd players , you know the components in the 80’s, i heard it sound and its way better than the components nowadays, why is that? It’s like the sound is coming from a live band especially the music of bon jovi Bed medicine i heard it from my uncles old components and the sound is astonishing.

Get the old speakers that were wired to the Sansui and wire them to the Sonos Amp with speaker wire of the right thickness for the wire length. If the old speakers are still in good shape, they will deliver the sound you refer to.