I used to love Jump Desktop. It turned my iPad into a Mac. Very slick, but in recent months, maybe years (not used it for a while), VoiceOver has stopped being parsed through the remote connection. I've tried reinstalling, different devices, changing audio output... The lot. Jump Desktop support weren't particularly helpful, saying that they had it working, but I don't know if they did, as I'm not sure they were quite understanding what VoiceOver is or does.
The interesting thing is there is sound. VoiceOver notification sounds work perfectly; it's simply the voice that isn't working. I'm using Alex if that makes any difference, but did also try with Daniel, the most boring of all voices.