I've been using NAT64 at home for a few years now. Most apps out there handle IPv6-only just fine, with steam and videogames being the exception.

A few older android phones had some issues, and I believe not MS product has ever worked (but these were all guests, so I didn't really bother much).

I'm amazed that this requirement is coming so late to iOS, seeing how (supposedly), apple tends so much to the quality of their apps.