Monitor screen covers can really help you protect your eyes both from the blue light and the glare.
However, they are not customizable. Sometimes you might want to see the real colors on the screen, but you won’t be able to.
So it might be a better idea to search for another option.
I can suggest you 2 things:
Blue light blocking glasses
Blue light blocking glasses are helpful again if you don’t need to customize the amount of blue light that gets blocked. In this case, it’s way easier to just take them off and see the real colors of the screen (if you are a graphic designer for example).
But once again – you can’t customize it.
Blue light filter
A blue light filter is the best decision in my opinion. It will block the blue light partly or entirely, you can adjust it. For example, your screen can emit 40% blue light or less/more. It’s all up to you and the light in your room.
You can turn it off when you need to see the real colors of an image.
The blue light filter can give you protection and flexibility to choose what you want to do.
That’s why I use a blue light filter too.