Should my game be blurred or native?

Should my game be blurred or native?

So, for the longest time my game has used a blur setting, for Gamemaker Studio it's called "interpolate colors between pixels" and does just that, it sort of smudges things over and generally makes a pixelated game seem smoother on larger displays. At least I think that's what it's for.

Anyway, the problem is that keeping this can cause several issues and I'm told it's not just a Gamemaker Issue but a D3D one. I've been trying to solve it, but so far nothing seems to want to fix this seam issue for scrolling backgrounds. Only when Interpolate is disabled does it fix it. This, of course, makes everything non blurry and makes pixels almost sand out too much on large displays (think blowing up Mario 1 to a 1080p display without filters turned on in an emulator).

Does anyone here have any recommendations? Should I keep all of my pixels native and just don't blur them out? Should I manually tweak them all to be slightly blured and then reimport them into my game? I just don't know what to do.