Problems with mesh in Scene

I am creating a scene in Blender and I don’t know if it was after using decimate or when exactly but the mesh looks very faulty also I am having enormous problems when rendering such as glitchs or “non response”

Is there a way I can clean my model and set it back as normal?

Not a lot of information here, but at a glance this looks like you might have accidentally duplicated everything in the scene.

Hi,

or try to narrow the scene and camera clip starting and end point:
image
image

Cheers

Julian