I don't udnerstand what you mean with changing the rigs to default. About the blur, disable denoising in the ray tracing settings.

If that doesn't work, I just found a solution that honestly I have no idea why it works but it's working for me: Create a new file in a previous blender version like 3.6, it can be blank if you want, then open that file in your current Blender version, now disable the ray tracing denoising and every model you add to said file should look fine.

Tell me if it worked and if you had to do the extra file step.