To delete “Siri and dictation history” , go to "Settings", then "Siri and Search", then "Siri and Dictation History", then "Delete Siri & Dictation History". To re-record your voice, go to "Settings", then "Siri and Search", turn off "Listen for Hey Siri"and then turn "Listen for Hey Siri" back on. It will ask you to "Set up Hey Siri" to recognize your voice. After that, it worked for me. You may need to turn off your phone then turn back on.
I'm sure there are different approaches but thanks to the post from binojmatthew
Oct 14, 2022 12:30 AM in response to BrittneyMcD
I was finally able to get dictation to work again.