Question flat shader with transparency

Hello,
I am trying to have a shader with a flat color but with transparency.
I tried ti use the particle shader for this but its rendering the blackfaces which is not what I want.
I just need a solid color everywhere in the mesh but with transparency.
Is there a way to achieve this?

 

https://forum.unity.com/threads/question-about-transparency-and-rear-faces.774224/#post-5213051
https://discussions.unity.com/t/models-using-transparent-shader-are-overlapping-themselves/226093

Has been discussed a lot. I think XRIT also has a shader that can work with this

 

Thanks for the info, but that's for URP.
Is XRIT a shader kit? Would you have a link?

 

I'm not familiar with built in shaders, but there are probably shaders available.
XRIT is XR Interaction Toolkit, but it has some shaders