Are all the projects setup the same e.g. HD, 4K, etc…
Whats wrong with importing 20 AEP in one project.
I do it all the time and avoids screwing up the original.
Much faster than opening one project at a time.
Then if your setting up in 3D you might have to make changes to the static frame so no need to open up the original project again.
I export all kinds of frames from PSD, JPEG, PNG, etc…
They all work to up to 30k pixels.