I'm a noob, so I'm probably messing this up somehow, but can anyone tell me why the materials preview looks nothing like the render? Below, I have two screenshots to illustrate this (the better looking one is the material preview). Using Cycles fixes it, but I'm curious as to why it's not working properly in eevee. Thanks for any help!
The material preview uses a built in HDRI to provide lighting and reflection information. You can add your own in the shading tab under "World" (highlighted below), by adding it as an Environment Texture. You can use any HDRI you want, but the ones that come built in with blender are in the blender folder at ../2.83/datafiles/studiolights/world.
If you want the reflections and lighting without the visible background, there are a few ways to accomplish this. The method I prefer is to connect the texture to two separate Background Nodes, and then combine them through a Mix Shader, using the "Is Camera Ray" output of a Light Path node as a mix factor. Doing it this way allows you to control the brightness/strength of the both the lighting and the background image independently (I set the background image to 0 in my example).
