Decide on a way forward (Check audio playlist widget, mejs, maybe react?)
I tested out the [playlist] shortcode in WP Core that uses mediaelements.js. Given its inclusion in core, it makes sense IMO to utilize it.
I tested it from a sighted, keyboard-only interaction and it's doable. The screen reader implementation definitely needs work, but I'm not sure how we would go about addressing it (via our own implementation or recommending a fix on the mediaelements repo).
Newspack has started work on an audio block, which includes a separate audio player from mediaelement.js. Also see pamTN9-T6-p2
After chatting with @jeffersonrabb about it, it looks like the PR is a PoC really and not meant for production. They have not looked at mediaelements (yet). AMP compatibility is also a concern.
Most helpful comment
After chatting with @jeffersonrabb about it, it looks like the PR is a PoC really and not meant for production. They have not looked at mediaelements (yet). AMP compatibility is also a concern.