Have you see the documentation that explains that you can download any compatible GGML model from Hugginface and configure Shotcut to use it?
Just click on the “Configure” button and specify the file you want to use. If you find some models that work good for certain situations, I’m sure people would be interested to know about your experience. If they are generally useful, I can add them to the list of models that Shotcut can download for a future release.