How to maintain sharp lines (pixel-like effect) from small textures on 3D assets

I have bunch of small source textures, 64x64 pixels. Example:

I want this texture to occupy a significant part of the screen, but scaled without any smoothing/anti-aliasing, even though it could cover as much as 640x640 pixels on the device. But I the result I am getting looks like this:

(Note the undesired addition of multiple brown colours - rather than solid blocks)

• I am using import settings which have the texture set to Clamp and Point.

• The camera has anti-aliasing turned off.
  

• The camera 'output' has MSAA turned off.

  • The material uses the Unlit\Texture shader

  • I'm using URP, but could switch to HDRP.

• I don't believe I can use the pixel perfect package, as that is designed with 2D in mind, and I am creating a 3D environment.

The effect I'm going for, is that like a old 1980's 3D game, 'stretched' to big resolution, with no clever sampling to soften the jagged edges.