In Spiderman: Far from Home, we see Tony give some of his technology to Peter Parker, specifically:
A massive, space-based swarm of killer robots, controllable through the Edith interface.
It seems that this system would have been very helpful, especially at the end of Endgame. Tony clearly didn't make it between Endgame and Far from Home. Are we given any indication as to why it is left unused until then?