I am using the gmail web-app to access emails from eg yahoo and outlook, well if they pull off the plug of this feature (gmail mobile app only) no big deal - sod off gmail (web app again) there is zoho that you can do this with a very small cost (abt £1/mo IIRC)
bad eyes here due to corneal erosions and cataracts, but I don't use voiceover, just large fonts+ inverted contrast - on linux anyway, Gnome.
I think windows have way better (quality) text2speech at least than linux
[0]https://en.wikipedia.org/wiki/Frapp%C3%A9_coffee