I can’t comment on UI Edge routers, but my UDM SE has perfect IPv6 support. Which, granted, is a recent thing (full support for SLAAC arrived about 6 months ago

I can’t comment on UI Edge routers, but my UDM SE has perfect IPv6 support. Which, granted, is a recent thing (full support for SLAAC arrived about 6 months ago), but no complaints from me about the UniFi line.