”how probability WORKS” is not probability theory and how probability is “interpreted” is an interpretation without “justification”. In fact, you are disingenuously making up an assertion about how probability is interpreted with an implicit temporal aspect. Probability theory has a frequency interpretation and a Bayesian one but no “poof it suddenly happens” temporal interpretation. That’s all yours.

“What is sufficient to make a wave "collapse"” is a legitimate question for applying the theory itself. There are cases where we don’t know a-priori whether a particular proposed setup constitutes an observation. Who is this observer? Saying that it is whatever is sufficient to collapse the wave function is a tautology.

Also, any interesting question is “legitimate” even if its underlying assumptions may be questioned.

Finally, this is my last response. While I enjoy discussing science, I’ve other things on my mind now. I live in Lebanon and we’re being assaulted by a genocidal country supported by a genocidal empire… quantum physics philosophy seems moot in my current circumstances.