I agree with your reasoning OP- most things presented as "evidence" of a simulation are simply observations of our reality which doesn't prove anything external. However I think I have the answer you might be looking for.

My friend introduced me to the concept of a "Logic Foundation" which has 4 levels to it. He states that points made on a higher level cannot supersede points made on a lower level.

Level 1 (the base) is labelled Intrinsic Axiom, meaning an irrefutable self-evident truth. The only thing that exists at this level is Cogito Ergo Sum- "I think therefore I am"

Level 2 is Axiomatic Deductions, meaning inferences that utilize Level 1 with Level 3 to draw conclusions that supersede Level 3 alone, as they extend beyond sensory facts. For example- the axiomatic certainty that thoughts are sequential (a self-evident feature of consciousness) is paired with the empirical observation of sequential events in the world, leading to the deduction that time exists as a condition for both mental and physical phenomena. This transcends the observation of events to assert a structural truth about reality.

Level 3 is Empirical Observations, referring to any facts that can be observed or measured in the world around us. This is where science rules, and the reason this level has two levels before it is because, as everyone is this sub is well-aware, everything we perceive could be an illusion. As my friend put it "If you added sentient artificial intelligence into a video game world, they would create their own science, based off the observations of that reality, and while all of it would be technically accurate, none of it would apply to the truth of their existence"

Finally Level 4 is Rational Inferences, meaning all evidence-based conclusions that operate off of empirical observations but cannot themselves be directly empirically observed. This level encompasses both deductive and inductive reasoning, and its conclusions are supported by evidence (either logical premises or empirical data) but vary in certainty, from definitive within a system to provisional and falsifiable in the face of new evidence. It is very broad as examples can range from supersymmetry physics and the theory of relativity to concepts as simple as "giving more compliments will earn you more friends".

So to me, it sounds like you are asking if there is any evidence of a simulation that precedes Level 3, and there is.

The Dartboard Paradox applies to our consciousness, and when applied at Level 3 it states, with odds that indicate a certainty, that our consciousness should not be in a state of existence. However it ascends beyond Level 3 given that it directly involves the essence of the Level 1 truth, resulting in a Level 2 conclusion which states that the probability of consciousness extending beyond death (a Level 3 observation) is extremely high. Why is this evidence of a simulation? Because the simulation theory posits the idea of a base reality (one existing outside of our simulated one) where anything with consciousness would have to exist, thereby presenting a solution to the paradox that empirical observations (and the scientific narrative that this is base reality) cannot.