Since lighting behavior can vary across Unity versions and render pipelines, you may need to add additional lights to achieve better-lit thumbnails. For HDRP, you can start by adding the following light: 1) Intensity: 0.5 | Rotation: (160, 0) | Color: White 2) Intensity: 0.5 | Rotation: (20, 0) | Color: White 3) Intensity: 0.5 | Rotation: (90, 0) | Color: White 4) Intensity: 0.5 | Rotation: (30, -110) | Color: White