There are multiple screenreaders but their voices simply suck. KDEs espeak has way worse voices than Android eSpeak for some reason.
There is Thorsten Voice, a grest project that sounds really nice.
Not sure if he has a espeak dataset too.
Do you know any others?
Its essential for blind people, I dont think any blind person uses Linux if they have to hear these robot voices every day.
Not sure if this is gonna be much better than the alternatives you’ve listed, but you can try adjusting pitch, rate, range, etc. with spd-say.