First sale since opening the account, thank God, after posting 49 photos

Since yesterday I haven't been able to upload new photos, even though everything is written correctly. I don't know how to fix this problem. If anyone knows how to help me, please do.

What are the areas that are very competitive?

What is the best AI image generator program you currently use?

Most of the images I uploaded to the platform were rejected due to quality issues. Is there a free platform you use to improve image quality?