Consumer routers don't support lots of useful stuff though, so them not supporting NAT66 isn't very surprising. Enthusiasts are likely to use OpenWRT or nftables, both of which support NAT66 [0], and quickly Googling some random enterprise routers shows that they all support NAT66 too [1] [2] [3].

This isn't enabled by default because it's usually a bad idea, but it's certainly possible if you really want. (It's discouraged because NAT in general is a bad idea, but it's no worse with IPv6 than with IPv4; the only difference being that IPv4 effectively requires NAT.)

[0]: https://openwrt.org/docs/guide-user/network/ipv6/ipv6.nat6

[1]: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/ipaddr_nat...

[2]: https://www.animmouse.com/p/how-to-nat-ipv6-in-mikrotik/

[3]: https://www.juniper.net/documentation/us/en/software/junos/i...