PhotoLab works differently than Lightroom for adjusting highlights and shadows, white and black, etc. Fortunately, the subject has been discussed here rather extensively. This might be a good starting point:
For simply recovering highlights, you might try making careful use of Smart Lighting (spot-weighted adjustment if the regular adjustment isn’t adequate), lowering exposure, or a combination of lowering Selective tone Highlights and raising Selective tone Midtones to compensate for the fact that the Highlights slider doesn’t just affect the brightest part of the image.