??
NDI is a protocol that was designed for using wired Ethernet, though if wireless environment good enough could support video bitrates (without the bufferng built into streaming devices like Roku, AppleTV, etc to overcome WiFi limitations)
Then there is websockets which OBS uses for receiving incoming commands from other apps/systems (and being much lower bandwidth, can work fine over WiFi, though wired Ethernet almost always more reliable)
so, not sure what you are asking
A Capture card is taking (typically a HDMI output signal and converting into an input video signal). You will be constrained by the HDMI output capability of the Gaming PC (ex CEC, etc.. HDMI extensions) and the capture card... but HDMI extensions tend to be associated with the HDMI signal itself, using that as a general network communication environment... no. Now, I'm aware of Ethernet over HDMI... but most likely your Gaming PC video output isn't designed to support such.
And one would reasonably ask... why bother?
- Using NDI over Ethernet is the cleaner approach, but would presumably have a greater resource impact on the Gaming PC (not my use case, so not 100% sure, but I'm presuming the encapsulating the video signal into NDI and sending on Ethernet isn't 0% CPU... though how much I'm sure ..depends
- Presuming hardware resource limitations (or Game DRM?) is why using Capture Card instead of NDI, you could still use websockets to communicate with OBS over Ethernet
