I record a video directly from the camera app, if I watch it from the gallery it plays with high quality. But I have noticed that if I share it on Whatsapp or Instagram (for example) the quality drops a lot (the colors turns palid). I believe it has something to do with the HDR10+ option because if I turn it off then the recorded videos, when shared, it stays with the same quality.
Also, if I record a short video with HDR10+ on and share it it also keep the good quality.
PD: I have the "convert HDR10+ videos when sharing" option activated in the gallery.