I use Ren'Py's built in self-voicing support on desktop platforms, accessible by pressing V. You should be able to access all controls using a keyboard, and I've tried to provide (voiced) alt text when appropriate. I've done a decent amount of extra work to make sure my game's specific features, like procedural text, are supported by Ren'Py's self-voicing.
The game does not support external screenreaders like JAWS, just the OS's built-in TTS. There's at least one open issue for Ren'Py itself to support screen readers via the AccessKit API, but there's no estimated timeline for that.
There are additional accessibility options built into Ren'Py on a menu accessible by the A key, particularly font options. These should work, but they're a lower priority to me than self-voicing.
Thanks for your interest! If anyone who uses these features has feedback or notices anywhere where the game doesn't seem to be using them right, please let me know! I don't have any major vision impairments, so there may be problems that I won't spot.