Ok, I see the point you are making. But When you say

quantum immortality must then run a consequentialist computation to distinguish

You are thinking of QI as an agent who has to decide what to do at a given time. But suppose a proponent of QI thinks instead of QI as simply the brute fact that there are certain paths through the tree structure of MWI QM that continue your conscious experience forever, and the substantive fact that what I actually experience will be randomly chosen from that set of paths.

I disagree with QI because I think that the very language being used to frame the problem is severely defective; the semantics of the word "I" is the problem.

The concept of "death" is too complex to be captured by any phenomenon other than the process of computation of this concept in human minds, or something derived therefrom.

I think that perhaps the word "I" suffers from the same problem.