First video = Sounds like a sneeze/cough.
Her crop looks a bit puffy. What does it feel like? I'd check her crop first thing in the morning before she eats/drinks to see if it's emptying.
The Second upclose video = her eye is slightly red with a sunken appearance and slight swelling of the sinus. Have you added wood chips/new bedding, etc. to the run? Your runs are all attached, so birds are all next to each other. If she has something, all are likely exposed anyway.
I'd consider starting her on Tylosin to see if that helps. Flush her eye(s) a couple of times a day and put some Terramycin eye ointment into her eyes.
Where did the new flock mate come from? Is the bird new to you or just from another pen/run/coop from your own flocks?
I'd still check her crop, if it's not emptying, access it by the article below.
https://www.backyardchickens.com/ar...w-to-know-which-one-youre-dealing-with.73607/