In my game (only the level 2 for now), my scene is about 10000 x 5000.
There are about 8000 instances of blocs or tiles of sprites.
There are rapidly loaded at the beginning: no slowing because i only use instances of some objects.
You must consider to reanalyse your project (ideal is before to begin your game)
Instead of Smooth Camera you could use a simple tween. There is an action “Tween the camera position”, call it every frame with “easeOutSine” and duration 1 second, boom smooth camera movement. The extension has extra bells and whistles which you may not need.
No, there’s very little code, and not code at all referencing to tiles. Lacking time I just erased like 3/4 of the map, and I am now making different scenes to alleviate the burden of the processor. (It worked).
Edit: I also wanted to write this. Making different tilemaps will also reduce lag, because when you have one tilemap it’s loaded fully, when you have multiples tilemaps, only those near the screen would get loaded. I hope it makes sens.