I'm a little sad that quantum immortality only works sideways and not also backwards

Quantum immortality postulates that when you "die" in one universe, your consciousness continues in another. (in a nutshell)

What it doesn't specify is that your consciousness can ever go back to an earlier point in time (that you remember, anyway)

Alcohol is great for nostalgia (e.g. "Hey, daytime whiskey, wanna meet my record collection?").