The evidence of your random shots, some of which are quite difficult because of the bright sky over a dark scene, appears to show that the camera is doing what it is designed to do. In an auto or semi-auto mode, it will meter the scene and attempt to move the tones to an overall average level.
For example, the first photo in Post #12 has over two thirds very bright sky and less than a third dark trees, so the camera has shifted the overall brightness down towards an overall average. This has resulted in the clouds looking dull and the trees almost a silhouette. This sort of scene needs positive exposure compensation to be set in the camera to restore the realism.
An opposite example is the last photo in Post #13 which has over two thirds dark trees and less than a third bright sky, so the camera has shifted the overall brightness up towards an average. This has blown out the sky (all maximum white, from which nothing can be recovered) and made the trees rather pale. Negative exposure compensation here might have been able to reveal some cloud detail (as shown in the previous example) while giving more realism to the trees. (If the trees become too dark, they can usually be brightened successfully in post-processing).
If you are getting random very
over-exposed images, when carefully considered exposure settings have been thoughtfully applied, it might suggest a problem with the lens rather than the camera - the aperture mechanism might have become stiff and sluggish with age (just like me!), so that it is not closing down to the required f-stop when the shutter fires.