how to make a 2d game zoomed but sharp?

how to make a 2d game zoomed but sharp? a game I'm playing currently renders on a small window, low res which becomes very blurry when I go full screen. What would be recommended to make the image as sharp as possible without losing quality?

I tried hq4x but it did not work as expected(made the image blurrier). Anything else I can try?

I would be curious to know a solution as well, although I doubt it is possible. The blur comes from the fact that the resolution is not native. But by doing native resolution, you would probably have really small assets on screen.

You would need to use an algorithm that is similar to Lanczos or Jinc. But since ReShade currently does not have resampling support, it doesn't seem possible.