I, for one, have the terminal value of continued personal existence (a.k.a. being alive). On LW I'm learning that continuity, personhood, and existence might well be illusions. If that is the case, my efforts to find ways to survive amount to extending something that isn't there in the first place

I am confused about this as well. I think the right thing to do here is to recognize that there is a lot we don't know about, e.g. personhood, and that there is a lot we can do to clarify our thinking on personhood. When we aren't confused about this stuff anymore, we can look over it and decide what parts we really valued; our intuitive idea of personhood clearly describes something, even recognizing that a lot of the ideas of the past are wrong. Note also that we don't gain anything by remaining ignorant (I'm not sure if you've realized this yet).