у меня вот такая ситуация:
bpy.data.objects["blaster_waves"].modifiers["blaster_waves_gn"]["Input_1_attribute_name"]
# 'position'
"Input_1_attribute_name" in bpy.data.objects["blaster_waves"].modifiers["blaster_waves_gn"]
#True
getattr(bpy.data.objects["blaster_waves"].modifiers["blaster_waves_gn"], "Input_1_attribute_name")
# AttributeError: 'NodesModifier' object has no attribute 'Input_1_attribute_name'
dir(bpy.data.objects["blaster_waves"].modifiers["blaster_waves_gn"])
# ['__doc__', '__module__', '__slots__', 'bl_rna', 'is_active', 'is_override_data', 'name', 'node_group', 'rna_type', 'show_expanded', 'show_in_editmode', 'show_on_cage', 'show_render', 'show_viewport', 'type', 'use_apply_on_spline']