How do I change the images that will be accepted?

Your assets are showing the typical artefacts of small sensor cameras like your iPhone 15. They look great on your screen, but viewed at 100% (one pixel on the screen is one pixel in your file), you see all the artefacts as a result of the small sensor, but also the artefacts because of those fancy software filters, like the portrait mode on iPhones. You can be sure that they will err somewhere in your picture, and that is visible in the file. Post your assets on social media, people will be pleased. But they are not to be used on quality stock media sites.

Neither is sharply focused, and as @Ricky336  indicated there are other artifacts as well. You cannot edit these to be in compliance with Adobe's guidelines. I wouldn't bother with submitting images of flowers unless you have found a rare and exotic species that is underrepresented in the database. There are already many millions of floral images in the database, and yours would never be found by a buyer or licensed.