Samsung Galaxy S20 camera cannot use the flashlight I wanted to use the light with the camera, then it said that some other app is using the light and I see that the two icons on the right on the top are faded out. It's so horrible getting a high-end smartphone and I cannot even use the light with the camera. What can I do?
The first thing I see from the image you posted, it appears there is a line through the Flash Lightening Bolt on the left, meaning it is disabled. So I would attempt that button first. Otherwise...
Exit out of the camera app and use the following steps. Go back to camera app after each one to see if it allows normal flash use.

Clear cache on camera app
Force stop one app at a time that you believe may be the culprit, stopping you from using flash.
Try another camera app.
Verify you have a working light with some flashlight app.
Verify your phone hardware is legit with one of the verification apps in the play store.

All else fails, you can always factory reset. But if it is all original hardware, it's probably from something you recently downloaded.