So how can it be done? Although I am not an expert in Starcraft lore, there seem to be some problems here. In such an adaptation, the show seems to be an origin of the Protoss, but the details seem inconsistent with the game.
In the show, one could see how the word "proto-molecule" would be abbreviated to "protos", to refer to the human hybrids with the "proto-molecule". Yatta yatta, this would eventually evolve into "Protoss".
The Problem
The Protoss in the Starcraft game are from a planet called "Aiur". There was no mention of them being created by humans. They do frequently refer to their ancestors, and live amidst sacred ruins of their ancestors.Important Details
In The Expanse, we learn that the creators of the proto-molecule were sending it across space in order to conjoin a super highway. The proto-molecule finds sources of energy and life to use in order to grow and create gateways when significant places are located.The Solution
The hybrids take over the belt, or portions of it . . . eventually. Perhaps they had taken over Earth or Mars at some point.In the meantime, they develop their own variants increasingly successful at mixing humans and the proto-molecule until they can produce new individuals without human beings.
Eventually, they take the ring gateway. They leave the Solar System, and shut down the ring. Earth takes control of Mars (or vice versa), and the existence of the Protos is covered up by the government as nothing more than a series of failed science experiments. The hybrids are commonly referred to as the "Protos".
All the while, the Protos are linked to their ancestors mentally/spiritually (as demonstrated in the show).
The Protos travel to the planet of their road-building ancestors: Aiur.
Although, they are connected mentally in a way that supersedes what humans are capable of, the Protos still develop a religion and language of sorts (as to match Starcraft.)
Over time, humans eventually develop interstellar travel, and they run into the Protoss again.
