Rewatched the GI show out of curiosity and caught something I missed last time:
Bryan Intihar said that they will not reveal WHERE Peter works until the game ships.
Horizon is too obvious. And why even save that? What surprise is him working at the company he creates in the comic? Doesn't make sense.
Oscorp is practically off the list because as Andrew Reiner stated: Harry's side missions have you checking in on Oscorp projects for him while he is overseas.
So...what could it be...?
I'm thinking Stark Industries. I think Peter works with Tony Stark who helps him develop the "advanced suit", as Insomniac calls it. The Avengers Tower, the Sanctum Santorum, and the Wakandan Embassay are all in-world...what says they can't fit in a Tony Stark or two? I'm not even sure he would appear on-screen. Maybe Peter is "house-sitting" for him, haha