Coqui is great, but in practice, I found Piper easier to set up, train, and deploy as an ONNX file. Big thanks to the Sherpa development team for their helpful resources: https://k2-fsa.github.io/sherpa/onnx/tts/piper.html and to the Rhasspy team for their training guide: https://github.com/rhasspy/piper/blob/master/TRAINING.md.

I also found DEMUCS + Whisper + pydub to be a super helpful combo for creating quality datasets.