Unlike canon, both Professors Turo and Sada stayed in Area Zero (Professor Turo does not leave when Arven was a very young child). They both are working (sometimes together, sometimes separately) on time machines, trying to find monsters from the past and present.
Only AI Sada exists, AI Turo was not complete prior to the machines exploding
When the explosions that kills both professors happen, it causes an anomaly in Area Zero, causing it to be “disconnected” from the timeline.
Area Zero alternates between being in the Scarlet universe (with ancient paradox pokemon) and Violet universe (with future paradox pokemon).
On occasion, other timelines may meet in their respective Area Zeroes. Shenanigans can and will happen.
In this world, only Koraidon(s) exisited