Need help finding a library/solution for efficient 2D tilemap rendering, collisions and interaction.

Hey, I've been looking for a while, but I was really hoping somebody could point me to a library that would help me re-code my engine as fast as possible into Unity.

Attached below is a really early shot if our old AS3 engine, and where I want to get to as fast as possible in Unity.

basically the map is defined as a very large 2d array of integers generated from code I've already rewritten in C#. What I ideally need is an engine/library that can help me render the tilemap, handle collisions, have some sort of optimization (I've heard a lot about needing to minimize the draw calls with tilemaps, and my lack of familiarity with the Unity engine is the primary reason I'd like to use somebody else's code for this part, at least to start with. The naive approach would be just to render each tile as a plane, then give them a width to collide with the sprite. I've done some early research, but I was hoping somebody might have more familiarity with the current options, I am not opposed to spending some money so don't cross off solutions that cost money.

The last requirement is I would like an easy interface for retrieving which tile the mouse clicks as a lot of logic for the game involves clicking tiles.

Thanks!