Maybe not exactly what you’re looking for but I found this a few weeks ago https://github.com/k2-fsa/sherpa-onnx and I haven’t really seen anyone talk about it

I’ve been using the tts on android for navigation and its way better than rhvoice and espeak.

I did try stt on android and it worked great but I’ve never used stt before so I don’t know how good it is compared to other stt