Your argument seems to use expected amount of copies to argue in favour of forgetting about expected amount of copies. In a way this is illustrative, an organism that only cares about sex but not about defence is more naive than one that sometimes forgoes sex to meet defence needs. But in a way the defence option provides for more copies. In this way sex isn't choosing to make more copies, it is only one strategy path to it that might fail.

Arguing about finiteness is like knowing the maximum size of bets the universe can offer. But how can one be sure about the size of that limit? There is althought an argument that a species that has lived a finite time will have only finite amount of evidence and thus a limit on certainty that it can archieve. There are some propositions that might exceed this limit. However using any probability analysis to solve how to tune your behaviour to these propositions would be arbitrary. That is there is no way to calculate unexpected utility and expected utility doesn't take a stance on what grounds you expect that utility to take place.