Under UDT, you care equally about every coordinate c, but will act as if you care mostly about c=2, because that is where you can create the most value with your decisions. (And same for worlds without the fifth dimension.)

It seems to me that this is where proofs of the Born rule by philosophers lend strong further support. The proofs, if I understand correctly, depend on assumptions that don't quite seem mandatory, but without which any decision strategy is practically impossible to specify or carry out. For example, the defense of "branching indifference" in section 9 of this paper:

If we are prepared to be even slightly instrumentalist in our criteria for belief ascription, it may not even make sense to suppose that an agent genuinely wants to do something that is ridiculously beyond even their idealised capabilities. For instance, suppose I say that I desire (ceteris paribus) to date someone with a prime number of atoms in their body. It is not even remotely possible for me to take any action which even slightly moves me towards that goal. In practice my actual dating strategy will have to fall back on “secondary” principles which have no connection at all to my “primary” goal — and since those secondary principles are actually what underwrites my entire dating behaviour, arguably it makes more sense to say that they are my actual desires, and that my ‘primary’ desire is at best an impossible dream, at worst an empty utterance.