I’m not sure if it’s just me, but when I zoom out it looks like the image gets slightly blurry.
And when you zoom in, to a certain amount, it gets clear again
Assuming it’s not a bug, this is likely the sampling method for canvas resizing. There should be an option for it in Krita settings under canvas. The options are usually ‘nearest’, ‘bilinear’, ‘trilinear’, etc. For the hardest resampling, choose nearest neighbor. This does have a drawback of making it look a little pixely, but it won’t blur the canvas anymore.