If the universe is infinite that should happen sometime (not really important) around 10^10^29 meters away. Of course, you don't actually have to die for that copy to exist either, and a copy of the local galaxy etc. is not too much further away (10^10^92 m), so waking up indistinguishably somewhere else after a good night's sleep would happen occasionally too.
Waking up up the equivalent memories requires a body with that arrangement of neurons that isn’t in ill health. That could easily be looking for a 3 on an infinite sequence of odd numbers.
Yes, at some point Boltzmann brains become higher likelihood but don't forget that interventions are not limited to prior history, e.g. someone builds a machine that performs whole-body surgery based on the timing of radioactive decay. Still more likely to end up with a functioning body than a Boltzmann brain. Most likely to end up with a weirder but more likely intervention (low expectation of it actually working, but not infinitesimal) (and from anthropic perspective)
The issue I was pointing to was a society with a higher technical standard isn’t going to naturally create a brain that remembers a vastly less technologically advanced civilization. It’s possible they would create such structures artificially, but now your dependent upon a civilization with the capacity that also happens to create this specific arrangement.
