Simplest way to move thousands of static meshes through an assembly line?

I am simulating the assembling of smaller pieces into larger piece and then the combined larger pieces into one whole.

This is a 15 minutes long sequence with a total of 11,200+ pieces, of around 20 unique parts.

All they do is go from point A to point B where they get combined into a new point A to point B, a few times as the units grow bigger and bigger.

These are all static meshes.

I envision using instanced meshes and the level sequence (which I am new to.)

Motion design can work but the workload is tremendous with key framing everything.

AI bots feel like an overkill.

Any suggestions?