Zeeskite, anyone who runs a treadmill after 10:00pm when noise is supposed to come to a halt knowing that the people downstairs have already asked you to stop, and run the washing machine before 9:00am, knowing that your downstairs neighbors also asked that you don’t, are not considerate people. No matter how nice you are to them, they are “selfish” and only do what is convenient and important to themselves.
If you want to dan l’kaf zchus i would say if she can’t do her treadmill before 11:00 which does not seem likely, then compromise and go down to listen what it sounds like, and do whatever is necessary to muffle the sound. But she refused to do that as well. So the OP tried to do the right thing but has no one to work with.