better settings to add high definition images to sprites

Hi! I’m making my first 2d game in unity, and I have a little problem:

I have several images, added to their respective sprite. I need each image to look well defined, but I don’t know what configuration to use to make it so.

Up to 8 images will appear on the screen, in squares. and currently they look very blurry.

I already tried to change the size of the camera, and the “pixel per unit” of the images but still, I can’t make them look good. I do not know if they are not the correct parameters to be modified, or it does not get the correct combination. I am new to unity.

Could you guide me? please

The biggest thing will be to use point filter and maybe no compression. I prefer one pixel per unit but not sure that has any effect on quality.