Here's a brief overview of how to use frequency separation to remove glare:

Duplicate the background layer twice.

Name the first duplicate "Low Frequency" and the second "High Frequency."

Apply a Gaussian Blur to the "Low Frequency" layer to blur out the details.

Select the "High Frequency" layer and go to Image > Apply Image. Set the blending mode to "Subtract" (for 8-bit images) or "Add" (for 16-bit images) and adjust the scale and offset accordingly.

Change the blending mode of the "High Frequency" layer to "Linear Light."

Use the Clone Stamp or Healing Brush tool on the "High Frequency" layer to remove the glare while preserving the texture.

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