I think it's creative but wrong to think that an agent could achieve quantum-suicide-level anthropic superpowers by changing how much ve now cares about certain future versions of verself, instead of ensuring that only some of them will be actual successor states of ver patterns of thought.

You can't change your preference. The changed preference won't be yours. What you care about is even more unchangeable than reality. So we don't disagree here, I don't think you can get anthropic superpowers, because you care about a specific thing.