Your debug log shows that DNS is resolving properly on Pi-Hole. With your NULL blocking, for both IPV4 and IPV6 it is returning NULL for the blocked site. What are you seeing that isn't working properly?
*** [ DIAGNOSING ]: Name resolution (IPv4) using a random blocked domain and a known ad-serving domain
[✓] marjoriex.com is 0.0.0.0 via localhost (127.0.0.1)
[✓] marjoriex.com is 0.0.0.0 via Pi-hole (192.168.1.60)
[✓] doubleclick.com is 172.217.18.14 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
[✓] kissesnstuff.blogspot.hu is :: via localhost (::1)
[✓] kissesnstuff.blogspot.hu is :: via Pi-hole (fd00::d9a:5ac:1286:4d3d)
[✓] doubleclick.com is 2a00:1450:4001:820::200e via a remote, public DNS server (2001:4860:4860::8888)