I got a (dual stacked) VPS that's running Wireguard.
My ISP doesn't provide me an ipv6.
So I just set up Wireguard on my Openwrt Router. Everything works, except ipv6.
The strange thing is, if I connect my phone directly using the Wireguard app I get a fully working ipv6.
But if I just use the Wifi I only get ipv4 working.
So to clarify, when you connect a device to your router's WiFi, that traffic is routed via Wireguard to your dualstack VPS, but only IPv4 connections are working?
If so, is your WiFi LAN properly configured with IPv6? It will not get a IPv6 automatically, since you aren't getting a IPv6 prefix via your WAN connection (as you don't have IPv6 support at home, right?).
Try to configure a static IPv6 address and subnet on your LAN. Either in the private range and NAT. Or if possible (IMO cleaner), use a static IPv6 address and subnet with a prefix from your VPS, so that you use publically routable IPv6 addresses on your LAN devices as they should have
If I remember properly, there is some issue with IPv6 in WG.
As a workaround you can leave the IP address field empty and create a new interface as an alias for the WG interface, where you will define the IP address.
Wirdguard is working fine with IPv6, I'm using it myself, but you do need to reserve a static prefix exclusively for your wireguard peers (and that is a problem on most consumer contracts with volatile prefixes).
This is all documented at the other thread I noted above. Also, I'm not sure what you wanted me to note in your other post - we know your IPv6 doesn't work, as you haven't assigned a Public IPv6 address.