Afraid not. All of the reviews/forums impression are very PC focused. And leave out some details. Tbh I never managed to find an answer to this with the older Hel or Fulla models (possibly made more complex by the different revisions; micro USB, AKM, ESS chips etc.).
I think it was always going to be a good product and absolutely work with PS5 out of the gate - i.e. anything that plugs in via USB will have access to Sony's 3D audio. The thing has so much power on it that I don't anyone is going to notice the 50%/15.75db dropoff if they just plug it into PS5. Basically the way that everyone on the internet seems to state that the SBX G6 works perfectly with the PS5 without mentioning volume drop-off or mic issues.
The bigger problems that tended to come up with the Hel were QC and latency. And I 'think' the Gunnr resolves the latter.
Hopefully we won't have to wait too long for
@WhiteHartMart to get a Gunnr and then politely ask him to test the volume on PC vs PS5