I have iPhone with brave. All YouTube videos are downloaded into the playlist in what appears to be 360 or 480. The original videos are available in 1080 or 2k.
I travel a lot and I download educational videos from YouTube before I board my plane. All videos downloaded go to terrible quality. The image quality is fuzzy, if there is small text on the screen I cannot read it.
I think it’s fair to request the feature that the quality be improved by AT LEAST good enough to read text on the screen.