Strange, every router I've used in the last 10+ years has done IPv6 fine. Even the RSP/ISP supplied gear I've used at friends/family houses are all fine with IPv6. Where I live all fixed line RSP/ISPs (except for one) has IPv6 enabled and on request will sell RSP-supported routers with IPv6 enabled out of the box. I personally don't use RSP-supplied gear but I've used Ubiquiti, Microtik, Netgear, etc routers and they all work just fine with sane IPv6 defaults. I really have not come across a single case of a bad IPv6 routers -- even among RSP-supplied equipment.