I want to use this for a 2D game and was wondering if it would work with regular sprites in a regular unity 2d project, or will I have to switch everything to the URP first?

Hi,

It works perfectly both in Standard Renderer and URP.

For 2D games there is a limitation. If you want to use URP and 2D Renderer, effects won't work.  2D Renderer curently don't support custom effects