@mzjo I'm sorry I never followed up on the examples you posted. The heavily scratched film is not processing related in the sense that it's a chemistry or processing temperature problem. The damage you show is caused by the emulsion side of the film dragging across something. This 'something' could for instance be a (semi-)stuck transport roller in the camera.
The best thing you can do at this point IMO is to systematically identify every place where the emulsion side of the film can come into contact with anything, from the point you receive the film from the seller to the moment you notice the scratches.