Convert Blur Shader to work with UniversalRP

Hi,

I'm building a mobile game where i want my background to be blurred out. I solved this by using a basic shader (from https://www.youtube.com/watch?v=YKTjVACAfqE) and everything worked fine until i started using 2D lightning. I have a UniversalRP as my renderer and the image with the shader turned pink (even after the built in conversion).

Does anyone have any idea how to convert this old shader to a new one, where an image blurs everything that is behind it in the order of layers?

Thanks for any help!