How to make the game go faster Unity 2D

I have a 2D game which there’s more than 800 box(and I can’t use Tilemap because I want each box can be destroyable,using Tilemap would destroy all,hope there’s be a new Update so I can use Tilemap).
How can I make the game have higher FPS?If I deactivate the box actually game goes good, but activating it even when I compile the game goes a little slow.

Set Up a script that activates Boxes based on camera distance, or maybe even use the functions mentioned here:

Check out C# Scripting in Unity: Script Optimization - Unity Learn