K, new theory, sort of.
It's a simulation, but not for Sensei, he's just a vehicle for that weird God Yasu worships. This God is the only "real human", he's narrating (at least sometimes) and probably have some brain damage or whatnot. For many cycles, Sensei was nothing but an avatar for this God, but at some point, probably because he acted out complex behavioural patterns for numerous cycles, he started to gain some authomy. That causes constant disconnections from God, or maybe it's the opposite, whenever he disconnects, God takes over. Maybe at some point, he went completely on his own and that's were his thing with Maya originates from.
Also, there are signs of conflict between whatever God Maya aligns herself with (Nozomu, the calous one?), that resides in Shrine and the Wire Tree God, the one Yasu worships. Maybe both of them trying to take over Sensei.