Learn how to make per-vertex and per-pixel pixelation.
Decompiled Art has released a short tutorial explaining how to create a pixelated retro effect shader in Unity using URP, HDRP, and ShaderGraph.
From the video, you will see how to make your models old-school with per-vertex and per-pixel pixelation.
You can then get the project files for $4.99. We also recommend checking out other guides from Decompiled Art on YouTube if you want to know more about Unity.