It is possible to combine all layers without changing the coloration.
Open the ① Layer window, and select Add Layer from Canvas from ② Add Special Layer.
The ① composed layer was added to the top. This layer will be used to demonstrate the Glow Effect.
Open the ① Tool Selection window, and select the ② Filter.
Select the ① Brightness & Contrast.
Drag the ①Slider until the color looks like the image above, then tap ②✓ button .
Select ①Gaussian Blur from the Filter again.
Drag the ①Slider of Radius and when it looks like the image above, tap ②✓ button .
Open ①Layer window and set ②Blend mode to ③Screen .
This is a comparative image. The look of the picture changes, by applying the Glow Effect.