Most Quantum Mechanics are formulated from a point of view of Causal Decission Theory, as can be seen from the Noncontextuality/counterfactual indefiniteness of Kochen-Specker Theorem.

Now, this creates a chatastrophe when the Observator needs to be analized through a physical lense. That is, Self-Measurement is terribly paradoxical.

Things go so badly that one needs to conclude that the following axiom is incompatible with the Law of Noncontradiction and Quantum Mechanics. According to Frauchiger and Renner:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6143649/

Suppose that agent A has established that

Statement A(i): “I am certain that agent A′, upon reasoning within the same theory as the one I am using, is certain that x = ξ at time t.”

Then agent A can conclude that

Statement A(ii): “I am certain that x = ξ at time t.”

How can we create a Quantum Theory of Self-Measurement that is compatible with Updateless or Functional Decission Theory (I don't know the difference between the two), which I deem more realistic for physical reasons.

I ask you this because I consider you the experts on Decission Theory. The answer to this question may have consecquences on my personal research in biophysical processing of information.

If you need clarification on Quantum Theory and its No-Go theorems to answer this question tell me.

Thank you on advance!!!!

I am not fully sure I understand your question, but this post by Scott Aaronson might be relevant:

https://www.scottaaronson.com/blog/?p=3975

And do problems also do not arise with Albert self-measurement in "The quantum mechanics of self–measurement"?

Thank you a lot!! It is useful!