Hi thecosmicpulse,
As Kent said, to set up your own posemorph.
This question also came up in the Q&A forum as well, so I have looked into it.
If I get the idea correctly (Kent is the authority here!), then the automated PoseMorph and Xpresso sqettings are all you get. The PoseMorph slider, as well as the RangeMapper in the Xpresso, is the end of the provided information.
The actual expression of the face itself is not transferred. Going by the name of each PoseMorph, these have to be set up manually and have match each name.
I have developed a few sketches for the development of workarounds:
https://www.cineversity.com/forums/viewthread/3961/
https://www.cineversity.com/forums/viewthread/3887/
But they are limited and more (as mentioned) a sketch. Please understand that a different mesh has a different amount of points. Besides that, each point might be located differently, comparing point ID numbers. Hence why the Moves By Maxon app can’t just magically transfer the Blend-shapes from the given mesh to something completely different. Here, so my assumption is the roadblock that you have encountered.
If you have a mesh that has the points as well the point ID numbers 100% congruent to the neutral MbM mesh, then it is an easy task to transfer. If so, please ask in the Q&A forum and share the two meshes, I will set up an Xpresso for you.
All the best, stay safe, stay healthy.