How to remove embedded drop shadow on background layer in PSE 2026

I've been using PSE forever and just recently installed PSE 2026.  I'm using it with the light UI (and don't want to switch to dark) and am noticing that the background layer appears to have a slight drop shadow embedded in the layer.  It's driving me nuts.  When working on some layouts, it makes me feel like my right and bottom edges are blurry.  Is there a way to shut this off?   I've tried creating a layer and hiding the background, and flattening layers, but the shadow sticks.  I just want a flat layer like before. This is not an improvement for me! If there is no setting to remove it, I am requesting that it be added to Preferences as something that can be turned on or off.  TIA