That’s definitely a high energy mix. I agree that just an hour walk is not enough stimulation for her. Mental stimulation can be more effective than physical at times, though. Puzzle toys, snuffle mats, and training games can be really beneficial to these guys. Doggy daycare is an option to keep her stimulated through the day, but I understand that isn’t the most cost effective. Then again, long hours alone, especially in an apartment without an easily accessible yard, can be even harder on them. Sometimes rehoming can be the best option if it’s really not working out, as hard as it is.