Caveats

In most cases, NAT is not used with IPv6 in any capacity as everything is routed. That is great for connectivity and for businesses or locations that can afford Provider Independent (PI) address space and a BGP peering, but it doesn’t work in practice for small business and home users.

Network Prefix Translation (NPt) allows one subnet to be used for LAN which has full connectivity via its native WAN, but also has translated connectivity on the additional WANs so it appears to originate there. While not true connectivity for the LAN subnet via the alternate paths, it is better than no connectivity at all if the primary WAN is down.
Warning: This does not work for dynamic IPv6 types where the subnet is not static, such as DHCP6-PD.