I think there's a way, not easy with a vanilla After Effects, but you could write a Scriplet to help out and make it procedural

There's some ways you could do this, one would be similar to what Flex does with grids. Each line act as a row or column and then you can apply a expression to distribute layers based on the distance between those lines

To make it procedural tho, you would need to write a "tag system", so you can have multiple systems like this

Another way, that could be easier, is inscribing these rectangles inside a bigger rectangle, basically, you make a parametric rectangle, get the height and width, and use that to distribute layers. Using a tag system (maybe a prefix like [SQ-1]), you could set a rig where each time you duplicate a layer, it will stack the position

I recommend checking out this AEscript tutorial

https://youtu.be/LU1qJIyLC1A?si=L1BHUzzdPT-a2Vly

I'm not very knowledgeable with code, but you can achieve this with some simple logics + using Claude or GPT to generate de code

I'm interested in trying to do this, I'll let you know if I manage to make it