There's not much you can do on console to optimize the game. It's technically already optimized to be able to play on Console. Additional packs will add to load times.
- Play in offline mode (if you can)
- Play on a small lot with just the basics to reduce the amount of items.
- Select minimum sim count via game settings. This will allow culling of unplayed households keeping the population small.
- Clean out personal and family inventory.
edit to add: I don't think you can lower graphic settings on console but you can try lowering resolution at least.
