Why is it taking so long to review?

Do you have a model release from Martin Luther King? If not, you should delete those, they will be refused. Also, you submit a lot the same assets, or very similar one to the other. That also will lead to a refusal. And typical one to two weeks means that you were very lucky.

I took another look at your screenshot and four of your images in the two bottom rows look like one and the same. You need more varied assets.

Have you read the Help?
Actual people cannot be registered.
When searching for real people such as celebrities or politicians, very few results come up.
These are assets that violate the rules and cannot be registered.

Darth Vader and Martin Luther King Jr. are easy to understand.

https://helpx.adobe.com/stock/contributor/help/photography-illustrations.html

This wasn't your questions, but one of the rules is not to submit the same image with different colors, as per the first four images.

I have images that have waited between 1 and 10 months, so no longer have an expectation what is normal or average or acceptable.