Thank you very much!! I haven't worked on pixel-art game before add didn't know that the filter is causing the blur issue, I tried removing the filter and it looks way better than before.
I always set PPU to the size of the image so that the image takes one unit of space in the game, I do that to simplify the math xD, I don't know if it is good or bad though. and I didn't know about the power of 2 thank you.