Hi,
thank you for your help.
It is not possible to set the static route in the application-PC because I have no access to It's operating System. Therefore I need to configure it with Router1.
In the meantime, I solved the Problem. I think, I did already set up everything correctly at Router1 because since I made a factory Reset of Router2, everything works fine and Packages will be delivered correctly.
Now also the traceroute shows the correct Path from PC over Router1 to Router2 and to the Internet.
Thanks,
Flo