SOLVED!! Shortcuts automation “speak text” uses wrong voice

The issue of shortcuts “speak text” action using a different voice than what’s selected is finally solved. The problem turned out to be the iPhone language was set to a generic/default English (without a variant specified). Once I changed that to [English US] everything started working correctly.

Head to Settings -> General -> Language and Region, look at the top of the screen where it says Preferred Languages and mine used to say just [English] so I clicked Add Language and selected [English US] from the list then shortcuts “Speak Text” started using the correct selected voice.

I hope this helps someone. I tried all the other suggestions on this forum and none of them worked (reset Siri, reinstall language etc etc) so I had to figure it out myself.