Look, I explained the details in the OP. Create a lot of Earths and hope that yours turns out to be one of them. That already violates causality, according to your standards. I don't see much of a way to make it clearer.
Ah - that's much clearer than your OP.
FWIW - I suspect it violates causality under nearly everyone's standards.
You asked if your proposal was plausible. Unless you can postulate some means to handle that causality issue, I would have to say the answer is "no".
So - you are suggesting that if the AI generates enough simulations of the "prime" reality with enough fidelity, then the chances that a given observer is in a sim approach 1, because of the sheer quantity of them. Correct?
If so - the flaw lies in orders of infinity. For every wa...
A self-modifying AI is built to serve humanity. The builders know, of course, that this is much riskier than it seems, because its success would render their own observations extremely rare. To solve the problem, they direct the AI to create billions of simulated humanities in the hope that this will serve as a Schelling point to them, and make their own universe almost certainly simulated.
Plausible?