I can't make "one" pixel when I draw

Good morning all,
so I have a problem that looks pretty silly ... I would like to make icons in 32x32 (so a bit like "pixel art") but when I put the brush at 1px, hardness 100%, it is not 1 pixel it makes me but 4, with 4 transparent pixels.

So I would like to have my pixel alone with a 100% color ...
I am enclosing a screenshot, with what I want on the left and the result I have on the right ...
if someone can help me it's great!
Thanks to all!