This is Story related and cannot be missed. Zeus is the final boss of the game. Defeat him and the Trophy should appear.
i found a video of the battle for those of you having trouble on God Mode or Titan Mode breakthroughs. I notice the key is parrying is Bolts and watching for his telegraphed moves to avoid.
All credit goes to Chasing Chickens whom ive linked their page
https://www.youtube.com/channel/UCYIBo2Vjk7S55-t9EiUbGdA