Before Illustartion Traditional, Now AI Photos. My sale down, what this is impact from my new asset

Whatever the reason is, it is neither AI nor non-AI assets. It's more the sheer addition of new content each day, that makes it more difficult to get your assets presented to potential buyers. I suppose that you will heve, however, more chance to find new buyers for non-AI stuff, as most what gets added is AI.

Many customers (myself included) search the database with AI filters—3-bar icon on left side of page. 

Are you contributing commercial quality content that's in high demand— lifestyle, travel, nature, tech, and business-related photos & videos? 

Stock is a numbers game. 

• The big net catches more fish.
• A diverse portfolio that appeals to a wide range of customers will be seen by more people.
• Good keywords & descriptions will help customers find your content in searches. 
• The more you sell, the more visible you are to potential customers.

Coincidence. The types of asset in your portfolio should have no impact on sales. In fact, more types of assets should in theory increase sales.