I have an iPhone 13 pro max, running the third developer beta of iOS 16.
I recently heard about some issues with the mail app, and confirm that I found one of them. Voiceover will not read the word reply. Therefore, if you want to respond to a message, you must use the reply all option.
At the moment, I’m using the Nathan voice, but may switch to a different voice, to see if this issue presents itself with other voices.
Overall, though, I would definitely give iOS 16, the grade of an a in the Accessibility department. Mail app issues in iOS 16 beta 3?