The ONLY OBD-II bluetooth dongle supported by the Kia Soul EV Spy app is Konnwei KW-902. If you google it, you get numerous, e.g. this: https://www.amazon.com/KONNWEI-KW-902-Bluetooth-Diagnostic/dp/B00Q5YRC4C
I don't know if there are clones / different versions of KW-902, so unfortunately I cannot guarantee that those works, even though both look exactly like mine on the outside.
The KW-902's I have are reporthing they are ELM327 v1.5, but even if they state they are that version, there is no guarantees it will work.
I believe Warrens statement that the Panlong dongle works well is a (slight?) exaggeration: At least one command sent by the Soul EV Spy is not understood by the Panlong dongle, and there sometimes seem to be glitches with missing data and/or timing issues occasionally. However, you never know what is causing that kind of thing (Android version differences, android device hardware, radio-interference).
@Warren: If your latest experience is that the Panlong now works flawlessly with the app, please email me your soulspy.log...txt and SoulData...csv files
There are a number of smaller ELM327 OBD bluetooth dongles reporting to be ELM327 v2.1 - I have 3 or 4 different ones, and none of them works with the Soul EV Spy app.