Fresh installed Raspberry 4 and got SSH and PIHOLE to run.
ping site outside LAN and get response. (ex. ping google.com - Reply from 142.251.41.46: bytes=32 time=10ms TTL=115)
ping my gateway and get a response
I couldn't see anything wrong with Pi-hole in the debug log – Pi-hole is blocking blocked domains and it is responding to DHCP requests correctly and it has an IP. It's simply unable to communicate with the network. Some things to check:
The network configured is 192.168.2.x, for example the router is on 192.168.2.1. Is this correct or could there be a typo, eg the network should have been 192.168.1.x and the router is at 192.168.1.1?
Is the ethernet cable plugged into a correct port, for example there are no VLANs or anything like that set up that might prevent the port from reaching the router?
Are you able to try another ethernet cable in case this one is faulty?
Has it been rebooted since installing Pi-hole? I know that seems a bit of a cop-out but, if not, it's worth doing just to see if it's something related to the installation process or whether it's something which now persists.
Try running the commands below in the terminal on the Pi. what do they give?