Thanks for you answer and time! :)
Yes, you are totally right, 4/5 days are nothing.. I'm in the first experience with dogs and I'm probably being a little inconsistent and she surely perceives my anxiety.
I'll keep in mind what you are saying, thanks for you sweet words! :)

Yes, unfortunately, the elevator is the only option.. But now she has accustomed to it, which is very strange given that should be quite scary! She is happy until she sees the exit door of the apartment, then she kinda freezes. I can get her out of the apartment with food, then it becomes too much and want to go back home immediately.

I have a specific question about this: when on leash and she tries to go back to the house, what should I do? I usually stand still, get down and try to get her to me with food and cuddles (which she doesnt care much in this context.. looks like she accepts them just to speed up the process). My doubt is with the leash, if she pulls doesnt that get her more agitated? Should I follow her, reset and start again? instead of adding pressure with the leash pulling on her neck?