I suspect that without further info from you, unless someone else comes forward with a DHCP-PD type set-up, it very much won't be fixed in 110-AIO! By trying to ping from the router you've already helped greatly in that debugging process - I now know that the router has a globally routable IPv6 address which it has obtained via DHCP-PD. The problem is handing out the obtained prefix to your local LAN. There has been a big step change from using a relatively un-intelligent programme (radvd) to something a bit more clever (dnsmasq), however dnsmasq is also a bit more fussy. The first thing I'm going to ask you is 'what is the prefix length?' If it is lower than 64 (eg 48/56) please try changing it to 64, reboot your router, try the ping test from your router and only if that succeeds, reboot your PC and try the ping from your PC. If the router ping test fails then I'll have to have a bit more of a think.