Nothing stops you running a NAT for v6 too, its just people tend to choose not to when given the choice
This really should be how SOHO routers do IPv6 out of the box.
Most people don't want 1:1 addressing for their entire home or office.
Are you using ULA prefix for the nat66/dhcp6, are you also allowing GUA address assignment via slaac? Im wondering how it works out with source-selection