When I try to use their OpenVPN files I can’t connect to Netflix.
Use the OpenVPN files on what? the router or the droid?
However, using another VPN (CyberGhost), it works great.
on what? the router or the droid? (yes it could make a difference!)
The server chosen is probably different for the Android App unless you specify the exact IP in both he router and Android.
Yes, if its not working on the router then the router is probably using a different DNS than the droid. Netflix is constantly adding VPN + DNS servers to their block list. This is not a bug in the router. Check the DNS leak tests with all of your VPN + DNS providers when accessing Netflix. Note the difference in reported server & location.