Fixing DNS Leaks with AdGuard Home on windows with IPV6 DNS

Ok, after testing some more I kinda see what is happening, it looks like my computer has a priority on the IPV6 DNS server, even with no IPV6 assigned to it, for now I edited my DNS Servers to be manually set, like this:
Is there any way of changing the IPV6 DNS Server when the tag is applied?

My computer (cabled), where I use the WireGuard App to connect to my VPN, when doing the test, it shows both my VPN and router DNS servers, hitting both at the same time. But when using PBR to redirect my stuff to the VPN interface, it only shows my router's DNS server. And here is the weird part, on every device connect to my Wi-Fi if I try to do the ipleak test, it shows ONLY the VPN server, even though every DNS server is similar to what my computer has.
You can expand the summary and see what I thought this was before actually doing some tests

Before digging deeper

Currently, I use tag classifier to my hosts with VPN, this is what is looks like:

config tag 'WGTAG'
        option dhcp_option '6,,'

config host
        option name 'notebook'
        option ip ''
        option mac 'C4:75:AB:xx:xx:xx'
        option tag 'WGTAG'

The first IP after the 6, is my VPN DNS and the following is my Router IP, where I use AdGuard Home to deal with DNS Blocking, I've switched VPNs and the new one supports IPV6 connection.
I've noticed from a device that uses IPV6, that when the IPV6 is assigned my computer tries to use the router DNS solution, causing DNS Leaks.

When using ipconfig /all this is the result:

DNS Servers . . . . . . . . . . . : fd5e:xxxx:xxxx::1

From devices with only IPV4, there are no leaks, only showing the DNS Server from the VPN (I think that with the current setup there could be leaks, since the 'second' DNS Server is my router). But on any devices with IPV6 both DNS Servers show up, the VPN and AdGuard Home servers.
It does feel like my current setup is redundant, and there could be multiple ways of fixing this, for example: disabling IPV6 DNS servers and not using AdGuard Home at all on VPN devices. But I would like to keep AdGuard Home on VPN Devices without a DNS Leak, any ideas on how to get this to work?

p.s. before the VPN switch I used Mullvad, and since they had their own Upstream DNS Servers, I used their stuff on AdGuard Home, but with this new one it doesn't seem like they have anything like that. My current VPN is AirVPN.

same issue as in How to set custom DNS instead of ISP advertised? ?

I'm not sure if DoH is the problem here, but I've just disabled the DNS service and RA DNS and removed my own router IPV6 from the DNS List, and when reconnecting my computer to the internet and after removing every DNS cache (here) it worked, but I really didn't want to just remove the DNS Server, if possible I want to overwrite it with tag classification.
Basically this:

config dhcp 'lan'
        option interface 'lan'
        option start '100'
        option limit '150'
        option leasetime '12h'
        option dhcpv4 'server'
        option dhcpv6 'server'
        option ra 'server'
        list ra_flags 'managed-config'
        list ra_flags 'other-config'
        list dhcp_option '6,'
        list dhcp_option '3,'
        -list dns 'fd5e:xxxx:xxxx::1'
        +option dns_service '0'
        +option ra_dns '0'

And I can definitely try to use the https-dns-proxy package.