Use Apple macOS Built in Text to speech
Select default text-to-speech voice to work with instant text-to-speech feature.
Instant text-to-speech feature uses default voice to read selected / entered text.
Select text and right-click to use context menu for reading with non-default voices and file export.
You can add more voices via macOS "System Preferences".
Open "System Preferences" with spotlight.
Select "Accessibility".
Select "Spoken Content".
To add more voices, select "Customise".
For example, to add more Greek voices, enter "Greek" to filter available voice, and select the voices you want.
You can also adjust voice speed via "System Preferences"
MP3 export with macOS tts is only available if users have "ffmpeg" package installed.
Users may use homebrew (https://brew.sh) to install "ffmpeg" by running:
brew install ffmpeg