Has anyone had a dog regress this much after a scary event?

Hi all, I'm curious if anyone has had a similar experience with their dog, or if anyone has any thoughts on what's going on.

We have a young rescue (1.5 years old) who lives with us in a downtown apartment. When we adopted her, she was somewhat timid, but over the first 4-5 months she made amazing progress. She was happily going on 2-mile walks, exploring, getting pup cups, and generally becoming a much more confident dog.

Then in late June, she had a couple of very scary experiences with fireworks while we were outside. Ever since then, it's like a switch flipped.

At her worst, she wouldn't even leave our apartment unless we carried her into the hallway. Now she has good days and bad days. Sometimes she'll make it all the way to her usual potty spot but get nervous and turn around without going. Other times she won't want to go very far at all. She seems generally anxious outside now, even when there isn't an obvious trigger. If she isn’t able to successfully potty after a couple failed “out” attempts, we have to take her to visit family.

Interestingly, when we have her stay with family for a while in a quieter suburban environment, she does well there. Much more relaxed, happily going outside and acting more like her old self. But as soon as she comes back home to our downtown apartment, the anxiety returns. It seems as if it’s very environmentally focused to the area around our apartment. Inside, she’s happy.

We're working with our vet, using anxiety medication as prescribed, trying to avoid flooding her, and celebrating small wins while encouraging her to keep moving forward.

Has anyone had a dog regress this dramatically after fireworks or another traumatic event? Did they eventually regain their confidence? I'd really appreciate hearing what helped and whether things improved with time.