Question URP and Sprite Sheets in 3D

I'm experimenting with particles in the URP and would like to be able to have particles render as sprite sheets with looping animation to add visual complexity. I downloaded a package with some older particle examples that use this technique, and the example files work fine under the old rendering system. However, when I try it with URP, I end up with a magenta mess. Obviously, the renderer isn't reading the sprite sheet correctly and seems to miss the alpha as well as the color. I just can't figure out how to correct this, nor can I find any tutorials on dealing with the issue.
I'm uploading a file to show how it looks. Under the old system, it just looks like a water splash. In URP, it looks like magenta rectangles.

 

Yup. The project is showing compiler errors. I've tried changing the sheder, though, without luck so far. I'm looking into making my own shaders in URP and applying sprite sheet textures. We'll see how that goes.