How to prepare a preview file for EVANTO (graphics)?

Question

Design

Hello! I recently found out about Evanto Market and decided to sell the logo on this site.
In order to send the logo for verification, you need to prepare several files, including a JPG image presenting the logo (width 590 pixels). Here is an example: https://graphicriver.net/item/car-line-logo/2983416 .
I have a logo rendered in illustrator and a set of textures.
The problem is that when I try to make an image 590 pixels wide and put a logo on it, making it smaller (1000 by 1000 pixels in illustrator) it comes out blurry and fuzzy. Although if you put the same logo on a 1500 pixel image, it turns out to be clear.
How do I fit the logo on a 590px image so it's crisp? In the example, all the pictures are clear!