Please start using the standard path location of files. I'm struggling with data merge handling thousands of images, which I would like to structure. Now I have to place all images within the main project folder, which makes it really messy.

This is not the way it should work, especially as we use this document on several different computer - which would make us change the master data every time we work with it.
C:/path/path/path/path/indesignproject/images/image.jpg

Ideal would be to follow the standard OS paths which would make it work on the computer your opening the project on without having to change the master data.
images/image.jpg

https://en.wikipedia.org/wiki/Path_(computing)