Never have two audio interfaces on one PC, only have one Audio interface and make sure one is the master clock, and feed everything else to that one as the hub for the pc. Tried the run the E2x2 OTG at the same time with the Topping E50 on one pc and found the sound now had jitter, and small clicks after firmware and driver updates. I think Topping needs to look into this. Did a wipe of my PC and only going to use the E2x2 OTG for my laptop and OTG only mode for the desktop. Also disabled motherboard audio card in bios as I will only be using the RME UCX II as the desktop audio card.
Connection to desktop will be using two line outs of UCX II into the line input on the E2x2 OTG (OTG MODE) and 2 line outputs to the UCX II, using the preamp on the UCX II for the mic input with the Rode headset adapter. This allows me to still use the E2x2 as an interface to my PC while using the UCX II.