How can I fix this?

Question

3D model decimated in Nomad Sculpt for UV Unwrapping before exporting into Procreate for painting. When imported back into Nomad, the model loses integrity.

I tried to smooth/increase quality of the mesh when in Nomad, which puts too much strain on iPad and crashes. You can see this poor quality in the final image within this project. I will be attempting to import painted Procreate model into Blender.