The S25U has 5 cameras, 4 on back and the selfie one, you might have to take some care to get the best pictures because the cameras don't all have the same resolution and focal length lenses. S25FE has 3 back cameras all lower res than S25U equiv. The cameras can have very poor quality results if you use them beyond their optical zoom range because the camera app fakes the zoom by cropping the frame expanding it to 4k if lower. You can lose massive amounts of detail from that.
It's often best to use the Pro or Expert RAW Photo mode and deliberately choose the best camera for the scene yourself and keep the zoom within that camera's optical zoom range. For most uses, the UW is 50MP and best used at 0.6x zoom only and probably most useful for very broad scenes, like landscapes because it has a huge field of view. It can also be useful when very close to a subject, even an inch or two away. The W camera is 200MP, often best if only used at 1x zoom but it also has optical image stabilization which can be very helpful with camera shake if you are not shooting a moving scene or panning to follow a subject. It's good for close subjects a few feet away, e.g. portraits. You will often get better results by zooming with your legs by moving toward or away from the subject. The T camera is 50MP with 1x to 5x optical zoom, the ST camera has a longer focal length but is only 12MP with optical zoom range of only 1x to 3x. Which makes the T camera 4x the resolution with optical zoom range that usually results in better quality pictures from the T camera than the ST camera. With the very large frame sizes of the UW, W and T cameras it's often better to do your own cropping to a preferred frame in an app other than the camera (Gallery, Photos, Lightroom, etc.). I find the frames are generally better with all AI enhacements turned off or to minimum.
The RAW file format produces larger filesize images that have better quality than jpeg format images. It would be most obvious at contrast edges such as between trees and sky.
Keeping the ISO setting to a minimum where you can handhold the phone without camera shake will avoid some "grainy" noise in frames. You can brace yourself or the phone on a solid, stable object to reduce camera shake (doing part of what a tripod or monopod does), even without bracing yourself or the camera you should get minimal camera shake using shutter speeds of about 1/50 second or shorter. A good way to hold the phone is to nestle the bottom in the edge of your palm at the same side as the "pinkie" finger. Nestle the side of the camera between your thumb and index finger and grip with your fingers across the back avoiding covering any cameras leaving your thumb over the front to make adjustments and release the shutter, or use your other hand to operate the controls. Keep your upper arm against your body and the hand holding the phone close to your body and use the three axes of your wrist to compose a frame. The phone, hence cameras, will tend to be more stable.
You can use exposure compensation to brighten a frame with dark areas you want detail in or darken a frame with very bright areas you want detail in. On the default camera it is an option with +/- in a circle, in the other modes it's called EV. Steps of about 0.5 positive or negative are common photography practice. Small values like +/- 0.5 to +/-1.0 are commonly used to improve ground detail in a day shot with sky in it (e.g. +0.5), or to improve general detail in a brightly lit room with dark areas (e.g. -0.5).
It can help to choose the focal point and exposure reference point by touching and holding the screen at the location you consider the "subject" in the scene. There are two automatic focus modes (center and multi-point) that can help if the scene has only one subject or multiple subjects.
These aren't the "right" way to take pictures, they are just common photography art/skill. You should be the artist if you don't like the camera's choices.
Oh yeah, and don't judge the quality of your pictures from the full frame view on the phone screen. The good S25U cameras generally have higher resolution than the screen. Either use the two finger pinch to expand the final picture view on the screen and scroll around it to look at detail or view them at a 1:1 view on a computer.
