This is a really nice campaign frame that can be slotted into any cyberpunk ttrpg. I think you do a good job of accomplishing the optional themes and challenges as well. The central arc of NULL is great, starting off more as a side plot that will eventually consume the campaign once its true nature is revealed.
I do think you could add a some more details on NULL for a GM and PCs to utilize though. Add a few more NPCs or factions that can act as "regulars" in NULL that the PCs to build relationships with. Additionally, adding some more notes on how these NPCs will react once the true nature of NULL is revealed will give a GM some more support for their campaign.
Otherwise, very solid campaign frame.