For EE, I find that the latest Clean Models works well.
For 1.69, I use nwnmdlcomp, but if that’s crashing, if I’m reading the wiki correctly, the old Clean Models is an option. Maybe the new Clean Models works if the model has no EE features? Others may know more.
Latest cleanmodels will work even with EE features but it won’t output things that work with 1.69. Not sure what you’d have to change to fix that but perhaps someone more knowledgeable can chime in.