What architecture to choose for this task?

Question

Software design

Task.
An application in which clients go through N processing steps (message exchange, for example, public keys, authenticated data, etc.) and then get into the general pool of users, i.e. the number of steps is non-deterministic.
After N steps, all clients can communicate with each other through the server.
The task is to do all this with strong typing (typescript) and an extensible architecture (you can add one more between the processing stages, the final pool should also be extensible in functionality).
Which pattern should be considered?
Middlewares seem to be inefficient, since the data coming out of node 1 is needed only in node 2, but not in the third, and middleware only increments data or refines - in my case, the interfaces of the results of work between nodes can be completely different.

Answer 1

workflow or state machine. Although they are very similar