After spending far too long on this problem, I thought I would post my solution that actually works as intended. The problem with other solutions is that either 1) the machine making the unstable core needs to wait until the product is finished before starting again, effectively adding another 10 seconds to the 40-second crafting time (so 25% longer), or 2) the unstable core beings to spoil the second the machine beings crafting it. This means that if the process is paused long enough (which will happen if it is lined up to make every 40 seconds), the crafted unstable core will instantly despawn instead of being crafted. Here is the blueprint - from my testing, it needs to be taken from the structure making the holo core, or from a chest.
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