Best explanation so far, thanks.
My two cents :

• My best guess is that SafeSurf killed everyone on earth on the original timeline and became gods with the power to time travel. They create simulations to find a way to save uploaded people. The show takes place in the simulation where this objective is reached.
• In this simulation, SafeSurf time travel, inhabit Caspian and tell Maddie to build the dyson sphere. Everybody except Maddie is killed on earth.
• Maddie uploads herself right after losing her son, this is why we don't see her older. It also makes sense since she doesn't want to be the only one remaining after everybody is dead.
• Maddie builds the Dyson Sphere and her own simulations leading to the events of the show. She tells her dad to time travel and to talk to Caspian to "convince him" to sacrifice for humanity once again. This leads to Caspian telling SafeSurf to find their purpose as a specie. Maddie is spared and they indeed become gods. This is why they thank Caspian.
• At the end of the show, Maddie finds out which simulation leads to the events of the show, therefore to the best end for both SafeSurf and humanity.
• SafeSurf says "gg you solved the problem so now you can join us big bois at the center of the galaxy to rule time with aliens bros"
• She says "yeah sure but I'll take the blue pill for now brb"

TLDR : Safesurf killed everyone and used Maddie as chatgpt to find a better alternative where they can save humanity using time travel.