Newborn congested for over 5 weeks!!

My daughter is 7 weeks now, she’s been congested since she was 2 weeks old. I’ve had the cool mist humidifier going, saline, suctioning, since I first noticed it. She’s been having what looks like retractions but her oxygen levels are always at 99-100%. (3 different doctors agreed it looks like retractions, her pediatrician said she could just be an intense belly breather) Her cough comes and goes. She eats well, no fever, very active baby. She’s been seen over 5 times, I’ve taken her to the ER twice. Tested negative for flu, Covid, rsv. And her lungs looked good on a X-ray. They keep saying she’s fine. I go back tomorrow. I just want answers. Has this happened to anyone else? What could be going on…. This can’t be normal