search the web for ffmpeg program. It is very techie but with help from YouTube on setting the parameters, you can adjust the gain for Y,U,V which is all you need to do. Another more costly approach is Adobe Premiere Elements for like $60. A little more user friendly.
If the processed image (not RAW) is over-exposed, it is clipped. There is no more data that will come forward if you pull the levels down. Some times careful grading in Resolve can make a blown out house wall look better by isolating whatever contrasty elements there are and tinting the remaining white areas slightly warmer. This is mainly a go-to with log footage from 10 bit sources, as the Mavic is just 8 bit you need to be careful when pulling the colors too much as banding will occour pretty fast. A blown out white sky can't be brought back, but a skilled colorist may paint it to look allright.
When I fly I expose and plan my angles for my subject, be it landscape, house, people or whatever. Often the sun itself will clip, so there is just a matter of deciding how big of a bright spot you want in your footage - traded for some more latitude in the shadows and mid tones. In general I leave just the edges of clouds in the highlights (use exposure warning and histogram), because clouds that are clipped half way in looks really bad in my opinion.
I agree that if you have highlights and saturate, you will loose all the data. But in JPG images, even with the ISP having the wrong exposure value, I can get to see much of what was "whited out" if I play the non linear transfer games in FFMPEG. I do mostly RAW when I test video at Amazon where I work, but I don't think anyone here is using DNG or RAW to get their images or data out. I just find that if you are 1-2 f-stops overexposed, you can still get some of the scene back to where you can enjoy it. If you have the 8-bit value go to 255 for a large section of image, then all is lost. But short of sun-flare, I can get much of an overexposed image back to "useful" but not great with FFMPEG.