The thing is, I don't even know **which** MWI Yud is trying to advocate for. He spends post over post going on and on about how he thinks that MWI is the most rational interpretation, but he never specifies which MWI formalism he supports, because there are many different ones and that is actually a huge point because one of the main criticisms of MWI is that phycisists struggle to find a consistent formalism for MWI that also doesn't make overly arbitrary assumptions. Yud entirely advocates for MWI because of ontological reasons and what is usually called "beauty" arguments. Since he never specifies a concrete formalism for MWi though he avoids every possible counterargument on wether or not his approach on MWI is even consistent with our observations and the rest of our theoretical framework. Let's take the most basic Everettian approach for example: The graph of the state vectors evolution is a physical entity. Meaning all of reality is described by a single wave function and all quantum phenomena are just that wave function branching. So everything essentially happens with a chance of 100%, just in different branches. A common criticism of this formalism is for example the following: Let us assume a wavefunction Y = a |i> + b|j> If we attempt to measure the sate of the particle now we should find it in state |i> with a chance of |a|^2 and in state |j> with a chance of |b|^2 . However, in a naive Everettian view, what do |a|^2 and |b|^2 mean? After all, if the wavefunction splits in two worlds, one in in which the particle 100% has state |i> and one in which the particle 100% has state |j> then the chance to experience |i> or |j> should be 50/50 since all branches are equally valid. So you need a mechanism that makes it at least seem like some choices are preferred over others. One could for example argue that during each measurement the wavefunction doesn't split into two branches but instead into an ensemble of branches where each possibiltity is represented as much as needed to replicate the probabilities |a|^2 and |b|^2 . However, one could argue that such behaviour is somewhat arbitrary because loads of completely identical realities would get created just for the sake of creating an arbitrary statistic and that this theory doesn't really explain quantum effects better than copenhagen, because you don't really have an explanation how the measurement device forces such weird ensemble creating from the wavefunction instead of just simple two-way branching. This is why MWI is far more complicated and on far less steady ground than Yud makes it out to be, because a consistent formalism of MWI still needs more extra assumptions than just naive wave branching. Serious proponents of MWI thus argue for much more nuanced and complicated formalisms than Yud's armchair physics.

What if "Q" or "C" are violated in such a minuscule way that it's not experimentally significant? Physical models only aim to describe reality, but might be not absolutely accurate, and still stay very useful.