I have exactly the same problem.
The sound is crappy and super slow.
I see that the sound volume can be changed in Batocera, but if I restart the system, the sound level is again at 100% (this does not save)
And the last point, on the ATOMISWAVE system, the KOF Neo-Wave games always block at the “clear data backup” level just before the introduction of the game, it is the only atomiswave game that blocks.
Thank you for your work.