import bpy
import math

layer_height = 0.003
rot = math.radians(90)
colec = bpy.data.collections['Pictograms']

for obj in colec.objects:
    obj.rotation_euler[0] += rot
    obj.location.y-=layer_height
    obj.select_set(True)
    bpy.context.view_layer.objects.active = obj
    bpy.ops.object.transform_apply(location=True, rotation=True, scale=True)
    bpy.ops.object.select_all(action='DESELECT')