I struggled with this issue for months. Over exposed videos cannot be corrected. So here's my approach.
The objective is to let the camera make a proposed exposure level. Then lock it in so it does not change during the shoot.
Turn on the Histogram
For video, set the exposure to Automatic. This is to let the camera do the work.
Point in the direction of your shoot and set your gimbal angle
Set focus to automatic and touch that part of the scene that is most important in your shot.
Let it focus.
Set focus to manual to lock it.
Select the exposure indicator (switch green square to yellow circle)
Set the Ev level to 0.0 using the wheel.
Touch the part of the screen where you want a balanced exposure
Let the camera set the correct shutter speed to adjust the exposure.
Check the histogram to verify things looked balanced. Don't worry about what the screen looks like.
If you want to ramp up the exposure or decrease it, use the EV wheel +/- a click.
Once you're happy with the histogram, lock the exposure by touching the AE lock icon (or if you are so inclined, you can set the 5 function button to lock and unlock the exposure). This will stay locked until the end of the video clip.
Shoot your video.
Seems like a lot of work, but you get used to it. Works for me.
If the shutter speed doesn't follow the 180 rule for shutter speed and frame rate, and that is important to you, do what
@Moose1967 says. You need a filter. That will slow down the shutter speed. It's like putting sunglasses on your camera.