Have you checked out if the Exposure is getting a little crazy?
In the viewport, under the Lit Menu, check out the Exposure. Set it to Fixed at Log 0 or some other values. If that fixes the problem then you may want to fix the Automatic Exposure in the PostProcessVolume. I saw you had one in the Volumes folder of the Outliner.
With the PostProcessVolume selected, under Post Process Volume, open the Post Process Settings. You can adjust the Auto Exposure values for Min and Max Brightness to prevent it to change too much, or not at all.
Check out the image: