Your debug log shows your Pi-hole to be fully operational for both IPv4 and IPv6 (click for log excerpt)
*** [ DIAGNOSING ]: Name resolution (IPv4) using a random blocked domain and a known ad-serving domain
[✓] pe-east.intentiq.com is 0.0.0.0 via localhost (127.0.0.1)
[✓] pe-east.intentiq.com is 0.0.0.0 via Pi-hole (192.168.0.2)
[✓] doubleclick.com is 172.217.23.14 via a remote, public DNS server (8.8.8.8)
*** [ DIAGNOSING ]: Name resolution (IPv6) using a random blocked domain and a known ad-serving domain
[✓] p279274.clksite.com is :: via localhost (::1)
[✓] p279274.clksite.com is :: via Pi-hole (fd00::70fc:7114:a1f6:9b24)
[✓] doubleclick.com is 2a00:1450:4016:806::200e via a remote, public DNS server (2001:4860:4860::8888)
Also, your IPv6 DNS server address from ipconfig correctly matches that currently in use by your Pi-hole host.
Note that dig -6 will force to use IPv6 for sending a DNS request for an A record to your default DNS server (i.e. Pi-hole). You'd have to use e.g. dig google.com AAAA to get an IPv6 resolution result.
Then again, neither of those options would affect the "Queries answered by" diagram, as that is showing how Pi-hole itself has retrieved a DNS answer, including which upstream DNS server it used. Pi-hole may decide to forward a query for a client's dig request to any of its upstreams, i.e. it may go to an IPv4 address now and to an IPv6 address with the next request, completely independent of how that request was received and what type of record was requested.
So there is no reason for concern at all with the diagram.
But the fact that your client's attempts to resolve DNS requests via IPv6 results in a timeout would suggest that something is blocking IPv6 from reaching Pi-hole.
This could well be your firewall on your Pi-hole host (likely) or on the affected client (unlikely).
By the above explanations, it should also be obvious that this wouldn't stop your clients from successfully requesting AAAA records and retrieving IPv6 addresses via Pi-hole.
This will work unhampered via IPv4.
Blocking IPv6 ports may indeed help to avoid seeing a diverse set of IPv6 addresses being listed in Pi-hole's Query Log, which could make client identification easier.
So as long as there is no other IPv6 DNS server available on your network, that would be a valid configuration.
However, to avoid risking a slow down in IP resolution (specifically for clients that prefer IPv6 over IPv4), you'd probably want to stop distributing an IPv6 DNS server address.in that case.