steps I had to take in order to get mozilla released model of TTS working with my mac! https://github.com/mozilla/TTS/

mozilla+tts.sh

pip install https://github.com/reuben/TTS/releases/download/ljspeech-fwd-attn-pwgan/TTS-0.0.1+92aea2a-py3-none-any.whl
python -m pip install --upgrade pip
pip install Cmake
brew install espeak
brew install libsndfile
python -m TTS.server.server
python --version
python -m TTS.server.server
pip uninstall flask
pip install flask==1.1.1
python -m TTS.server.server
pip install jinja2
pip uninstall jinja2
pip install jinja2==3.0.2
python -m TTS.server.server
pip uninstall itsdangerous
pip install itsdangerous==2.0.1
python -m TTS.server.server
pip uninstall werkzeug
pip install werkzeug==2.0.3
python -m TTS.server.server
pip install numba==0.48
python -m TTS.server.server

Errors encountered which cause me to find update packages to specific version. It is slow in synthesizing but far better than OS default TTS service

tts 0.0.1+92aea2a requires flask==1.1.1, but you have flask 2.1.3 which is incompatible.

ImportError: cannot import name 'escape' from 'jinja2' (/usr/local/lib/python3.7/site-packages/jinja2/__init__.py)

ImportError: cannot import name 'json' from 'itsdangerous' (/usr/local/lib/python3.7/site-packages/itsdangerous/__init__.py)

ImportError: cannot import name 'BaseResponse' from 'werkzeug.wrappers' (/usr/local/lib/python3.7/site-packages/werkzeug/wrappers/__init__.py)

ModuleNotFoundError: No module named 'numba.decorators'