Hello, I´d like to understand why were my photos rejected..
Adobe gave you a basic reason. What was it please?
Unfortunately, you have JPEG compression artifacts. If you zoom in you can see the artifacts in the blue sky,
And for the sun shot, the sun has turned out to be a white blob, so that isn't good.
I'm afraid all of your examples suffer from artifacts, and the composition isn't that good as well.
The photos have to be pretty good and well composed to get accepted.
Have a read of this from Adobe about how to create better photos:
Taking photos for Adobe Stock is more than just taking a holiday snapshot. (These look like holiday snapshots.)
the girl in the swing has chromatic aberration; several have leaning horizons...
Some of your pictures, besides all the technical faults, do have also IP problems:
Great pictures! Perhaps due to my lack of experience, I do not see the problems that other participants have indicated. Of course, with signs and people, they have problems to reject. Over-processing. Enhanced contrast. Be sure to resubmit them with other changes. I did it that way.