fsmithjack - If you are still using Jriver 19 to play local files, you can do a lot better. I use the free combination of Linn Kinsky/Minimserver/BubbleUPnP and it beats Roon, Twonky and Jriver by a mile. If you want to give this a try, I can give you more details. First download all three apps.
I use it with my UPnP Ethernet renderer, the Interchange:
https://www.audiocircle.com/index.php?topic=156409.0
This renderer delivers 10psec of jitter at the end of a 4 foot coax cable.
BTW, the Interchange outputs I2S on HDMI connector, compatible with PSAudio.
Also, you are correct that USB is fundamentally flawed, however if you add this device, it is very close to the best Ethernet renderer (assuming that you are using good USB cables like Wireworld Platinum and a good quality XMOS isolated USB interface):
https://sotm-usa.com/collections/sotm-ultra/products/copy-of-tx-usbultra-regenerator-1
Steve N.
Empirical Audio