The way it's supposed to work is the ISP delegates a prefix to the user's router, the router will advertise for that subnet and client devices will use slaac to

The way it's supposed to work is the ISP delegates a prefix to the user's router, the router will advertise for that subnet and client devices will use slaac to configure their ipv6 addresses. Meanwhile for IPv4 it operates as normal. For incumbent, mostly wired, Western ISPs that means a pool of IPv4 addresses and subscriber level NAT. For everyone else, that probably means CGNAT.