NPTv6 is different from IPv4 NAT and doesn't really have the same issues.
A different solution I've seen proposed for networks with multiple ISPs is to advertise both public prefixes to the network and let each client endpoint figure out which egress to use. This seems like a worse idea though.
The most official approach is to get your own public IPv6 prefix and work with your ISPs to BGP route that to you on both links. However, home and small business ISPs generally don't offer this.
A different solution I've seen proposed for networks with multiple ISPs is to advertise both public prefixes to the network and let each client endpoint figure out which egress to use. This seems like a worse idea though.
The most official approach is to get your own public IPv6 prefix and work with your ISPs to BGP route that to you on both links. However, home and small business ISPs generally don't offer this.