[✗] Failed to resolve doubleclick.com via a remote, public DNS server (8.8.8.8)
[✗] Failed to resolve doubleclick.com via a remote, public DNS server (2001:4860:4860::8888)
That's the issue that needs to be fixed. Pi-hole is working, it's responding with 0.0.0.0 for a domain that we know should be blocked. The problem is a query to a DNS server off your network (an upstream DNS server) is failing. That's a networking problem. And if that is not solved then a re-install of everything won't fix it.