Good day Victor! I am glad to be able to provide assistance to you today. I have checked this on my end and I have the same version of Edge for iOS and it is also not working with regards to the read-aloud for a PDF and for this it is highly suggested to also send a feedback to the team that is working on Edge and hopefully a fix will be applied soon on the next update and you can provide a feedback from the browser itself by tapping on the 3 dots > Help and feedback.
Regards,
Paul R.