Thanks for writing this!
On iPhone, you can use the Amazon Alexa app to read Kindle books for you. It's a pretty good listen given that it's not a human reading with full context -it only getting a little hung-up on occasion with some punctuation etc. (Caveat being that I've only used this method for about 1hr so far)
Guide here: https://redeemingproductivity.com/make-iphone-read-kindle-books/
I found this method today in my desire to find a way to listen to the tome that is The Matter with Things by Iain McGilchrist, which doesn't have an audiobook option.