#copy this to blender scripting panel after creating a new text file there. 
#run it only in a new scene to alter all the materials to alpha clip, full roughness and
#closest texture filtering. 
import bpy
import os

for material in bpy.data.materials:
    if material and material.node_tree:
        material.blend_method='CLIP'
        for node in material.node_tree.nodes:
            if node.type=='TEX_IMAGE':
                node.interpolation = 'Closest'
            if node.type=='BSDF_PRINCIPLED':
                node.inputs['Roughness'].default_value=1