All is in the tile, when I fly in direct sun, my shoots always over exposed and the sky is almost all white, I've seen some shoots in youtube having optical flayers when they fly in direct sun which is awesome, I've asked the owner of the video if he used a post edditing stuff to obtain a clair sky in direct sun with these cool obtical flyers and the answer was NO, one last thing that confuse me, I wanna know if when I shoot in 4k 50fps and watch the footage in 1080p the quality will be better then when I shoot in 1080p 60ps ? assuming that in both case I'll watch in 1080p even if the video was taken in 4k 50fps.

Bellow the footage I'm talking about.

Use the shadows highlights function in photoshop to remove the extra brightness afterwards. If you stop the camera down, the area under the sun will be underexposed and in shadow.