There are more than two Claudias

Okay. Let's assume there are two Claudias in Netflix's Dark. One from Jonas's world and another from Eva's world. Jonas' Claudia kills Eva's Claudia and she takes her place, collecting information from both the world. So far so good.

You're forgetting that there are other ways of there being alternate versions of the same person, e.g. that there are also two Jonases who are both from Jonas' world:

• The Jonas who gets saved from the apocalypse by alt-Martha, and ends up being killed by one of the alt-Martha's in Eve's headquarters. (Let's call this world Adam-A)
• The Jonas who saves himself from the apocalypse by running into the basement and will eventually grow up to become Adam. (Let's call this world Adam-B)

The point here is that there are alternate Schrödinger-like universes.

There are more than two Claudias. At the very least, there are three of them: Adam-A, Adam-B and Eve. It's unclear to me if Eve's world has a similar A/B split. If it does, that makes four Claudias.

Claudia has knowledge sources that don't reset when a cycle repeats

How can she remember all that? Because it's proven that one reality's incidents are not remembered by other realities' incidents, that's why Jonas can't remember when he was saved by Martha from Eva's world.

Claudia has two unusual sources of information: her own notebook, and conversations with her older self.

In the Adam-B world, Jonas spends 33 years of his life, from the 2019 apocalypse to 2052, together with young Noah and middle age Claudia, trying to invent time travel.

During this time, old Claudia repeatedly meets middle-age Claudia and passes information along.

Claudia also keeps a notebook where she analyzes the entire chain of events, which is passed inbetween time and therefore is able to transfer knowledge from an "older" person to a "younger" one, which means that this notebook avoids the death/rebirth cycle that people go through, which causes them to forget what happened in the last cycle.

Both of these knowledge sources, because they can be handed down from person to person, are able to avoid the fact that people from the next cycle don't remember what happened in the previous cycle (or the alternate Schröidinger universe).

All Claudias seem to be on the same page

Contrary to some other alternate versions of the same person, all Claudias seem to have the same character and the same overall goal: Regina's survival.

They also have had a lot of unfettered access to devices that allow them to freely travel around time and even to the other universe.

While the show never gave us a complete picture of where Claudia has and hasn't been, in her conversation with Adam it becomes clear that she has travelled all over the place, in both universes.

It's perfectly possible for middle-age Claudia to have been visited by multiple different old Claudias, or other ways in which the Claudias gathered their knowledge in that notebook, which seems to know everything about all of the universes and Schrödinger-dimensions.

In short, we don't know every detail, but Claudia is provably:

• Working towards the goal of collecting information about the entire cycle and all of its universes
• Unified in vision between alternate versions of herself, willing to cooperate.
• Ends up with the most knowledge of anyone in the story, also ends up solving the puzzle and resolving the final plot.