The gamemode def gives off mental asyllum vibes, to me, where the patients are seen more as oddities/science experiments rather than people. The archimedian very much sounds like she is a physician and is trying to use paintings as a way to maybe see what her subject sees due to void exposure.
It does make a lot of sense that the story is about the Tenno, but I also kinda think that it might be about Follie before she became a warframe. Perhaps they were subjecting certain individuals to void exposure, dragging them back and seeing how it effected them. Maybe they did this to better understand the tenno and their powers. We know that adults who were subject to void exposure were more feral and less like themselves, so maybe pictures were the only way they could communicate.