Drawing rectangles, lines, etc. on a 2d plane

Hello, I am completely new to Unreal Engine but not to C++.

I am working on trying to understand an existing game (which I do not have the source for). I am currently interested in writing an algorithm to automatically navigate through the world. This requires understanding their navmesh. The files of the game represent the world with rectangular cells for the world and triangles representing objects.

Currently, I would just like to use Unreal Engine to project/draw all of these shapes on a 2d plane as a visual aide for my understanding. I would also like to eventually like to draw lines between these cells or triangles to represent the optimal path. I am not looking to use any baked in navigation goodies of Unreal Engine, I only want to use it as a visualization tool. I know that there may be better tools for such a primitive task, but I would like to import the game’s map into the engine in the far future.

tl;dr, I am essentially looking for guidance on the right way to do something like this in Unreal Engine. I would appreciate any tutorials on how to programatically draw rectangles, triangles, and lines on a 2d plane, best practices, etc.

Thanks!