Glad VMIX is working, freeze may be something else but make sure you are not sending too fast or slow. Perhaps there is a difference in clock rates. Anyway, it encourages shorter overs.
OBS is a different set of problems. I tried various solutions and I settled on a a script using OBS Virtual Webcam (no sound...), OBS via FFMPEG Recording to the PC or Nano to be transcoded. This involves setting a relatively high rate in OBS, say 8Ms and getting the Nano to deal with it via a set of utilities on Evariste's git hub. You can also send HDMI to ethernet with the LKV373 or as G7JTT suggests and pick it up with the Nano to re-encode. This is what I am doing and it seems the most stable.