Brock's character has to be fleshed out before he becomes Venom. They have to make you believe Brock's hatred for Peter and why he wants him dead. Green Goblin will come, but Venom definitely needs to show up. He's Spider-Man's ultimate villain.
Jensen Ackles for MCU Venom!
My take on a new Spider-Man trilogy
1st movie: Kingpin and Vulture with Eddie Brock in a minor role
2nd movie: Kraven's Last Hunt with a Sin-Eater subplot, Spidey having the symbiote from Infinity War
3rd movie: Venom