TBH I’m not seeing how to do that with Omniverse Kit (I no longer have launcher and USD Composer), and the files were sent to me from a client - all of which is my problem, and I’ll keep looking into it. I guess the process would involve either flattening or changing the materials entirely.
However, in more general terms (and again I have to flag up USD newbie status) is it fair to say the main issue is with MDL shaders not being supported except via a connector, and those connectors now being deprecated?