Not if you want SLAAC to work in each LAN. Basically in IPv6 each LAN is supposed to have a /64, that's the real minimum allocation by design. Per the official

Not if you want SLAAC to work in each LAN. Basically in IPv6 each LAN is supposed to have a /64, that's the real minimum allocation by design. Per the official recommendations, ISPs are supposed to give every individual customer at a minimum a /56.