How would i optimize a game like this?

Hey i have a small deconstruction game, here is the video for it:

https://storyxpress.co/video/kmvfunc68vmkr1pf1

so there are many rigid bodies that i destroy as soon as they either touch the water or move out of the camera view, and i have the buildings deactivated until they pass a certain checkpoint then i activate it that's how the buildings come up in the video you watched.
i have all the rigid bodies on kinematic until the player "ball" passes a trigger that activates all rigid bodies on the structure.
I know this is definitely not the right way of doing things so i was wondering if you can tell me how to do this properly it would greatly be appreciated!