Maybe , @captainsteve may help you .
The quality of power output from the Powerwall is governed by the inverter. It may not be that clean. The Enphase IQ7+ microinverters on my PV array output AC at no greater than 5% THD. There’s also the recommendations per IEEE 519 on THD in power delivery.
I managed to find a post from someone who took images of an oscilloscope showing the waveforms for mains and Powerwall power.
The Tesla PW+ is an AC battery, so its new solar inverter converts array DC to AC then the internal inverter makes it DC for storage. Then output again is the internal inverter going back to AC. But as has been pointed out Tesla gives no stats for THD beyond <5%
Paul from PS Audio says its a waste of time, but he's also selling high end regenerators. I think there is something to be said for just having a dedicated circuit from the sub box the battery feeds for b/u to the house. That I can isolate and feed just to my music system. No other grid or household connectivity.