Question Switching to URP broke lighting and materials

Hello,
I wanted to use Volumetric Lights in my project and bought an asset that required URP to work. So I followed Unity guide to switch the existing project into URP and converted objects in the scene.
Everything became very bright and what is more, lighting doesn't light anything any more, doesn't matter whether it's a new or old light object. I turned off skybox and all environment light, but it has 0 effect. Some objects lost their materials (there are materials, but they are not displayed properly), some are displayed with artefacts, almost all assets in the project became purple. I wanted to revert the actions, but it's not working.

Am I doing anything wrong? I tried to google, but couldn't find anything useful on the internet.

 

Converting to URP requires more adjustments, there are features missing from classic, like ambient color, and there are brightbess bugs with the lighting in recent versions for the lit shader.

 

Also need to check if you are using gamma or linear color space

 

I use Linear as per guide. I tried to switch over back to Gamma, but it didn't do anything.

I tried different settings in "Lighting" settings window. Tried to create a new light, remove it completely. Basically clicked everything, but nothing moved at slightest.