Please note that with Interrail you'll have a 2 days limitation in your country of residence (Germany in this case), no matter the duration of the pass.

If this is an issue get Eurail and travel with your non-European passport, there is no such limitation.

Thanks

Hey, yes, you are.

Hey, Thank you so much for answering my queris. 

Just one QQ: I have a residence permit and work at an organisation on Germany and live in Berlin. But. I am not a German National. Am I still eligible for interrail pass?

Pass use: https://www.interrail.eu/en/interrail-passes/interrail-mobile-pass

https://youtu.be/Vl0gcQPqoW4

City travel: generally NO.

Pass is not valid on Metro, Tram, Bus. In most cities it is valid on a commuter rail but often this will not be much use for a tourist. The cost of buying day passes or paying single fares within a city will nearly always be cheaper than a day of a Eurail/Interrail pass.

How and where to book seats: https://www.seat61.com/interrail-and-eurail-reservations.htm

As you list your nationality as German an Interrail pass is what you will be eligible for, if you are not from Europe then it is Eurail.