DSC_2299.JPG - The boulders are underexposed in the shadows and blurry. The horizon is curved, which might be cured by applying Lens Correction in Lightroom Classic.
DSC_2297.JPG - If you zoom in past 100% you'll see that the boulders are not in sharp focus; there's also a lens spot just above the tallest rock.
DSC_2298.JPG - Rocks here are also unfocused, underexposed in the shadows, and the lens spot exists in this frame too.
Makes a lot of sense, when you know that the message you get is erronous.
When you post here, you need to tell us the rejection reason. I could guess what asset was refused for what reason, but as the assets are common subjects, all can be getting a refusal for “similar” as similar also includes assets already in the database. However, sometimes the message you receive doesn't make sense.
Compare your work with current Stock inventory. If Stock has 20 million or more of those assets on hand, they probably don't need any more at this time. Find other subjects to submit that have less representation. When submitting batches of similar images, you risk having some or all of them rejected. Choose only your best ones and mix them up with other subjects.
Quality issues are another matter. Whatever you submit must be commercial-ready content. That's what Stock customers pay for. Examine your work at 100-300% magnification. Correct all defects if you can. Discard the ones you can't. Also read these links.
I photograph landscapes and places in Sardinia, and it is hardly credible to me that there are many similar images of the places I have photographed, the problem is certainly another, saying that there are images already forwarded is a mistake.Like saying they refuse me a photo of a beach just because they have millions of photos of beaches.
After looking through these, they all have quality issues. Dust spots, exposure issues, unlevel horizons and lens distortion. From a technical standpoint the rejections are correct. Dust spots don't move between shots, so it's easy to spot them through a series and I was able to zoom in and see these in the same spot through several photos.
For the "Similar Images" rejection, it can include both your portfolio and images already in the database. If you search with your top keywords and titles I feel confident you'd find some similar photos. This has come up several times recently, and every time I've had no trouble finding similar photos in the database.
The 10 photos themselves also appear similar when quickly flipping through them. I believe this also can cause a "Similar Images" rejection.