Thank you for posting.
I am not a Windows user, and last time I tried the EPUB reader in Edge,
it did not work properly --- but in fact it was December or January, so
I guess they updated it at some point.
BTW, besides the free samples from ReadBeyond, there are some ~80 titles
in EPUB 3 reflowable + Media Overlays ("Audio-eBook") from the Italian
audiobook publisher "il Narratore audiolibri":
https://www.readbeyond.it/portfolio.html --- unlike the free samples,
whose audio comes from LibriVox, these titles are narrated by
professionals and recorded and edited professionally. Too bad there is
basically no market for this product, outside Kindle+Audible...
Best regards,
Alberto Pettarin