I had the same exact problem, only able to access to access the unraid ip in remote tunnel connection.
When I set `enable docker` to No than all of a sudden I was able to ping google.com as you mentioned.
your solution works in the same exact way for me, I have changed eth0 to using a static ip, and now able to turn on docker and user internet.
What Works:
Able to navigate through my LAN
Access the internet using my home IP address while on my cell network/etc.)
Can access docker containers and containers that I had set with static IP addresses
hit the unraid webgui
What doesn't work
Unable to access my router to modify settings at 192.x.x.1