How do I increase the resolution of my sprites without increasing their size?

So basically I built all of my levels (2d platformer) already without adding the graphics of the platforms etc. It's all based on the basic grid of 32x32. While creating my graphics I realised that they will look completely pixelated because most platforms have the low basic resolution.

So my question is: is there a way to scale my level up without me having to rescale every single element again?

Thanks!

In the project bar, change "sampling" from point to linear, that may solve your problem.