Would a theory of everything let us predict every event?
A complete physical specification and an all-purpose prediction algorithm are different things. A finite observer may lack the inputs, memory or time needed to compute a particular consequence. Some predictions can require running essentially the process being predicted. General computational undecidability also prevents one universal method from settling every program's behavior; whether a particular physical construction realizes the relevant computations needs its own proof. OPH's self-reconstruction proposal asks inhabitants to recover and realize their world's organization, not to store a lossless inventory of all events inside one head. A useful theory can constrain observations and interventions without granting omniscience. Calling it a fixed-point solver does not evade those limits or automatically reveal a person's future choices.
See also Can everything true be proven?, What does it mean to call the universe a fixed-point solver?, Could infinitely many physical operations finish in finite time?
Also in Chapter 37: Why Does the Loop Have No Beginning?, Chapter 40: Does It Feel Like Anything, and What Is Left to Decide?.
This answer comes from OPH, Observer Patch Holography. OPH is a rigorous, consistent and complete description of the unified, self-creating computational Universe we inhabit. Its consistency is machine-checked: the fixed point at its core is constructed explicitly, and a theory with a model contains no contradiction.
To understand OPH and check every step yourself, start with the free book Reverse Engineering Reality. It builds the theory from the ground up, and the OPH Notebook answers your questions while you read.
read the free bookask the notebookor ask sage:read chapter 2: Why Is There Anything Rather Than Nothing?watch a universe make its own particles