STEP file meshing with NGLib

We use nglib in a slightly modified way to mesh STEP geometries and use it further. Off late, there have been several meshing failures in the surface meshing of STEP files that read as UV Bounds Exceeded or some Area related failures causing, in all, 4-10 faces to fail. Interestingly, the same file meshes fine in Netgen GUI with a set of settings (Moderate, max edge length set to some small number, and avoiding STEP/STL/IGES close edges disabled).
My specific question is: what all steps does the netgen GUI perform in meshing a step file that I need to replicate to mesh a step file with nglib? Currently I do it as: open STEP file with OCC, mesh edges, mesh surface, mesh volume. I set the same parameters as before.

My initial estimate is that the step of Analyze Geometry in netgen GUI based operation does something to curb/merge/repair bad faces or small faces that possibly are present in the geometry. I dont know how to do this step in nglib based operation. Any pointers? Thanks!

Hi,
usually the meshing steps are Mesh Edges -> Mesh Surface -> Optimize Surface -> Mesh Volume -> Optimize Volume.
Maybe you lack the optimizations, which would create a better surface mesh and then the volume mesh could fail.
The string optimize2d in the MeshingParameters specifies which optimization steps are done in which order.
There is a function for healing the occ geometry, but afaik it is not called implicitly...
Best
Christopher