I will add this:
I think the solution is another Relic, depending on which ending you take. That's another reason I think the Aldecaldo ending will eventually lead to V's survival, as they have looted a ton of Arosaka tech (including another chip, which by the credits they don't know they have yet).
V is an engram in this ending, as per Alt. So they plug her engram into a Relic, and insert it back into her body.
Yes, it's painful - the new Relic working to rewrite the body to match V's engram, just as the previous one made changes to V's body for Johnny's. V's friends and family look after them, hoping for the best - and V does, in the end, come out okay. Probably physical therapy, need for implants as some parts of the body are messed up, but survives. Thrives.
(I know, that's my spin on it - but I don't know why the option of finding another Relic was never suggested, especially after V is turned into an engram).