Different environments need different transition models. Jordi Palet Martinez makes an important distinction in his @ripencc Labs article on #IPv6only vs. #IPv6mostly: https://labs.ripe.net/author/jordipaletm/ipv6-only-vs-ipv6-mostly-appropriate-use-cases/

#IPv6-only with #IPv4aaS, especially #464XLAT, fits mobile, residential and unmanaged access networks.

#IPv6-mostly fits managed corporate networks, where administrators can control host behavior, #DHCPv4 option 108, #NAT64, #CLAT and exceptions for local #IPv4-only resources.