Ah right I see. Yeah you connect to Owncast from OBS via the unRaid IP.
You may have to adjust the hardware resources or the stream settings in Owncast itself if you're experiencing buffering the Owncast stream page. My Owncast is set for 3000Kbps but you'll have to tailor yours for your hardware/bandwidth. There's also a buffer/delay setting to be mindful of, too low and your end users might have issues.
With regard to OBS. I have the stream set to use the x264 CPU encoder, CBR, 3000Kbps, fast CPU usage. I tried NVENC but the result was a pixelated stream on the Owncast side. Remember Owncast does a transcode of it's own.
My setup is OBS on a Win 10 VM hosted on unRaid streaming to Owncast docker on the same machine. I have four cores (8 threads) assigned to both the docker and the VM. I also tested tested it from various bare metal machines ony CAT6 network with no issues either. I wouldn't recommend trying this on WiFi though.
Feel free to ask any more questions if needed.