Any way to improve lighting of asset thumbnails?

I have a ton of prefab objects in my library. Ever since I updated Unity to 2020.2.1f1 the prefab thumbnails seemed to change from 'fully lit' to extremely dark:



They used to look more like this:



Is this something that can be fixed easily? The bright thumbnails really helped me to grab stuff at-a-glance, but now I have to squint when I have big lists of thumbs to make out what they are!

Thanks for any advice that can be offered on this.

 

I am wondering the exact same. Prefab previews are very dark and it makes it not as useful as it could be.
The best would be (for HDRP) to be able to specify a postprocessing Volume Profile that would be used for the previews.