Do you have then 2 cables from the RigPi to the TS-590S?
I can understand if you do, it is because this RigPi can be connected so many different ways, and none of them is wrong.
The only trouble is sometimes that there can be confusion where the audio for TX and RX and even the PTT is coming to and fro.
And in my thinking, the USB cable is so simple once it is fully configured.
It carries both RX and TX audio plus the serial data for CAT control which includes PTT.
So, for some first tests, can we reduce to just one cable, the USB A to B cable only from the RigPi to the radio.
Then, with that, do you still have good receive audio?
And about Power on and off with the TS-590S. My remembrance is that it can be turned off, but that it did not turn back on using the RigPi button.
It may be that a Macro can be made to do that, but I use another method to turn gear on, so I did not spend any time on that before.
We can visit that at the end, but first, let us work on the audio.
73 - Mark - K8MHW
'A RigPi Enthusiast!' - I am not otherwise affiliated with MFJ or RigPi