Ok, so we know that Cyn became part of Uzi in Episode 8, as we can see, it was due to Uzi swallowing Cyn’s core.
If we go back into episode 7, we see how Cyn clearly ate Doll’s core and if we apply the same logic, Doll would be part of Cyn’s consciousness. How do I know this? If we go to 16 minutes and 58 seconds of episode 8 and we slow down a lot, we can see in Uzi’s hud the words “RUS” which means Russian and “Doll.”
Which would suggest that doll is still alive but as part of Uzi’s consciousness. So that means that the shadowy figure that looks like Doll in the end credits might be Doll’s consciousness, so Doll might still be alive, as a showdown in Uzi’s mind.