QGIS - Exporting a raster layer without smearing individual rasters (so you can zoom)

I’ve been working with a raster map in QGIS (a shape file made up from squares) and now I’m trying to export it. I want to create an overview map for Germany that allows some magnification to look at individual rasters of 1km². My problem is that QGIS is sort of smearing the individual squares, smoothing the edges.

It also looks like this after exporting it even on 1200 DPI. If I set the scale of the map to a very small scale this doesn’t occur, but obviously I don’t want it to occur at all.

How can this be done?

Edit: Export Settings:

I’ve reset it down to see if that changes anything, but it also happens on 3k DPI.

Edit2: This is how it looks in a pdf:

As you can see now we have sharp edges (still no squares) and the squares are also missaligned.