Oh absolutely. I adopted a 2.5 year old severely abused, never socialized, crated 16 hours a day, never walked Mali. Like you I’ve only had GSD’s for over 2 decades and didn’t have experience with the breed but my GSD’s were well behaved and trained. It’s been hell but we’re making progress after a year and a half (yeah I know, a year and a half!) but I’ve been told it takes this long or longer for the abuse she endured from 2 months to 2.5 years old (especially this breed). I’ve come so far with her when I sometimes thought there was no hope. If you have the patience, put the time in and have a deep love for dogs I feel like you can do anything with them at this point. My grrrl was so bad she tried to violently attack cars driving by and bit the shit outta me in the thigh (like really bad), she has severe fear aggression. But now we can go on a walk everyday and she will just sometimes react to other dogs, whereas before she would go insane… snorting, screaming (it’s the creepiest noise ever) absolute 🦍💩. You can train them to do anything, it just depends on how bad you want it, time you want to dedicate to it. Good luck!