You misunderstood what
Chettlar was saying.
On PS5, the 3D audio is produced by the console itself, so the Pulse 3D headset doesn't have to do it itself. So it doesn't. It doesn't have that ability. And when you plug it into the PS4, it still doesn't have that ability. You can still hear sound through it, the mic still works, etc., but there's no 3D audio, because the headset itself doesn't offer it, and neither does the PS4.
If you talk about a different headset, designed for the PS4, and which offers 3D audio itself, then yes, those headsets will offer 3D audio on the PS4. But the Pulse 3D is not one of those headsets. It's designed for the PS5, where the console itself creates the 3D audio.