I'm aware that there is a RAW legal exploit to create an infinite number of simulacra of yourself as a wizard. You cannot do it with just simulacrum, as the spell itself limits you to only one simulacrum at a time. The spell states:
If you cast this spell again, any duplicate you created with this spell is instantly destroyed.
I cannot find a clear and simple explanation of the core mechanics of this exploit. It's always bundled up with some other plan. There is this question, which is mixing it up with some convoluted plan to kill all demons, and with extra complications from using a sorcerer. There is this answer, which is mixing it up with another convoluted plan to create hordes of undead.
It seems to me that the payload in these questions really does not matter. If you have an arbitrarily large number of archwizards, other problems become trivial.
So how does that exploit work? My understanding is the following:
You need a wizard that has both simulacrum and wish memorized. Ideally they have all their spell slots unused. Level 17 is the first level where you can do this, as you gain access to ninth level spells.
Create a simulacrum of yourself, using the normal process, and consuming a 7th level spell slot. You now have a simulacrum that has a wish spell memorized.
Ask your simulacrum to use wish as an on-label effect to creating another simulacrum of you. Since this is neither casting the simulacrum spell again, nor is it a duplicate you create of yourself (the simulacrum is creating it and it is not you), you now have a second simulacrum of yourself, identical to the first one. Only the first simulacrum used its 9th level spell slot.
Repeat step two as many times as you want, by instructing your simulacrum to pass on the instructions that the new simulacrum should follow your orders, should create yet another simulacrum of you, and should pass on these instructions in turn. You end up with an arbitrarily large number of simulacra of yourself(*), all of which used their 7th level slot, and all but the last one used their 9th level slot, and all of which follow your orders.
Ask the simulacra to do whatever you like.
(*) If you want the process to be finite, you would need to include in the instructions that when a simulacrum is the nth simulacrum of you, it should stop instead. Otherwise this process will continue forever.
Is this a correct summary of the exploit, or am I missing something?
