Siri and Speech - Why is it different and not as good as it should be? Feedback on text to speech for Speak Screen, Maps, Siri, etc.

I have an iPhone XR and iOS 12.x.

There appears to be a difference between the Siri voice and the Accessibility Voices.

Under the Accessibility settings there are "Enhanced" voices that can be downloaded:

Settings > General > Accessibility > Speech > Voices > English > Samantha (Enhanced)

Under Siri the "Enhanced" voices are not available:

Settings > Siri & Search > Siri Voice

One would expect that these would be related. It is unexpectedly confusing & disappointing that they are dissimilar and we are unable to have Siri utilize the "Enhanced" voices.

For example, I often find that the Siri voice used by the Apple Maps app does not pronounce road/street/highway names very well. I would hope that the "Enhanced" voices would improve upon this and be available across all of iOS.

I would like to utilize the "Speak Screen" more (under Settings > General > Accessibility > Speech > Speak Screen). However, when I use this (for example in the Apple News app) the text-to-speech is disappointingly monotonous. One would expect that the "Enhanced" downloadable voices would take advantage of the A11 Bionic's Neural Engine & ML platform to improve the pronunciation and language structure to sound more "human", but it doesn't. It should be able to interpret where emphasis and pauses in sentences should be so that sounds like a human is reading them. Instead, it reads everything like a run-on sentence in complete monotone, exactly like a machine would. (Actually, it doesn't even sound as human as "HAL".)

I would love to be able to queue several news stories from the Apple News app to be read to me while I go for a walk. Sadly, there doesn't appear to be a way to do this...and even if there was, it would just be depressingly dissatisfying to listen to with the current implementation.

PLEASE integrate the voices available via the Accessibility options with Siri and enhance the text-to-speech so that it is bearable.

Thank you!