What @abmet said, more information please!
Try this, set the ISO to 6400, the shutter speed to 1/250, and put the lens’ aperture switch to A. Go outside during the brightest time, around midday or early afternoon and see what you get.
The f-stop should be a large number, the lcd should show you the scene. It could be a little dark. Then try moving the aperture switch back, set the f-stop to wide open and try again. The image on the lcd should be brighter.
There is a setting to dim the displays’ brightness,
https://fujifilm-dsc.com/en/manual/x-t5/menu_setup/screen_set-up/
that may be affecting what you are (not) seeing.
