Best sounding local TTS engine I've heard by far is Kokoro
It's small enough to be run on modern phones realtime, I use it for listening to PDF's/EPUB as Audiobooks
https://huggingface.co/hexgrad/Kokoro-82M
Here is TTS under 4M: https://huggingface.co/owensong/Inflect-Nano-v2
Here is TTS under 4M: https://huggingface.co/owensong/Inflect-Nano-v2