I also don't think you really want a GSD.
Mine is GSD x Dobie (rescue but no abuse, she was born in a rescue centre).
She is super intelligent - I'm not always sure people think this through. I think people hear intelligent dog and think of them performing tricks and acting to command beautifully.
What it actually means is that she's like living with a velociraptor.
She worked out how to open all the doors.
She's worked out how to open the bin.
She learns how to press your buttons to get what she wants very quickly.
Yes, she learns new tricks in record time for treats. But if you don't have treats then she'll look you up and down and decides whether she pities you enough to bother.
Most of the time the answer is no...she yawns in your face and then ambles off giving you a side-eye look that says 'no chicken...no tricks human, I'm not stupid'
She's unpredictably reactive with other dogs. Sometimes she can be nervously sweet, other times (especiallly if anything yaps at her first) she goes full on Ronnie Kray.
She's absolutely adorable, very affectionate, is like my shadow and my best friend.
I wouldn't change her for the world (I lie...I wish she'd be more bloody obedient) but she is not the dog you're looking for!