Enable IPv6 with when no PD (Prefix Delegation) is available (ND Proxy) for Mac and Windows devices

I have a new default configuration vanilla OpenWrt 24.05.4 installation with the GL-MT6000, my ISP TMHI (T-Mobile Home Internet) doesn't provide PD (Prefix delegation), I only get /128 and /64 addresses with a 64 subnet, I can't create more subnets, therefore, I think (I am not an expert) I have to use Neighbor Discovery Protocol (NDP) Proxy, these are the steps I followed in LuCI Interfaces:

WAN6
1.- Created a WAN6 interface
2.- Assigned to firewall-zone WAN6
3.- DHCP Server --> Ignore interface (disable DHCP for the interface)
4.- IPV6 settings --> Designated master checked
--> RA-service = relay mode
--> DHCPv6-service = relay mode
--> NDP-Proxy = relay mode

LAN
1.- DHCP Server --> IPv6 Settings --> Designated master unchecked
--> RA-service = relay mode
--> DHCPv6-service = relay mode
--> NDP-Proxy = relay mode

Everything else is default, as soon as I save and enable, all the clients get immediately two IPv6 addresses (2607: --> T-Mobile), but, only the Linux (Debian, Ubuntu) and Android clients pass the www.test-ipv6.com test right away, the macOS, iOS, iPadOS and Windows clients, can take up to an hour for them to start passing the test, questions I have:

  • Is this because the NDP process takes time to discover those devices?
  • What is different with macOS, iOS and Windows IPv6 client's implementation that makes NDP so slow?

If I use another GL-MT6000 router with GL's firmware that is based on OpenWrt as well, in the GL GUI --> Network --> IPv6 there is an option called IPv6 passthrough, and if I use it, ALLthe clients will get the same two 2607: IPv6 addresses, but they also get a third address fd15:, what is GLi.Net doing differently? I checked the MT6000 configuration in LuCi and I can see they are also using NDP Proxy with Relay Mode.

Any help will be appreciated to get clarity on what is going on and trying to speed up the NDP process for macOS, iOS, iPadOS and Windows devices while using vanilla OpenWrt with the MT6000. Thank you