The problem is, if the 'from' entity is destroyed, it has no agency any longer, and the 'to' entity, if a perfect copy, won't notice anything different, it'll b

The problem is, if the 'from' entity is destroyed, it has no agency any longer, and the 'to' entity, if a perfect copy, won't notice anything different, it'll be like waking from sleep. There's no loss for the rest of the world. What if actual sleep is analogous to that? The you that wakes in the morning is a fresh copy with memories up until you 'died' last night. Definitely digressing into sci-fi thought experiments.