How do I Pixel Rounding a single sprite?

I wish I could enable or disable the pixel rounding of one or another sprite...

But it doesn't seem possible, does it?

It's entirely possible - all the option does is round both the scroll position and object positions. You can round those positions yourself on a per-instance basis.

If you allow fractional scrolling though it gets tricky though: if the left of the viewport is at say 100.5, then you will need to position an object at a 0.5 offset in order to have it aligned to a pixel on-screen. It is probably easiest to always round the scroll position, so you know if an object position is rounded then it will be in the right place.

Which option take off the blur of the sprite?

I wanted to choose this option for certain sprites, and not for others.

Idk if it is pixel rounding. sorry by mistake

That's the project sampling property instead. Currently this is only supported project-wide.