You may try Downscaling in project settings, according to manual.
Downscaling
Adjusts the tradeoff between rendering quality and memory use when resizing images to smaller than their original size (downscaling). The options are:
Low quality: mipmaps are disabled (reducing memory use), but downscaled sprites may appear blocky or pixellated.
Medium quality: mipmaps are enabled. Downscaling sprites generally looks better.
High quality: mipmaps are enabled and the spritesheet after export pads out all images to power-of-two sizes. This can significantly increase memory use, but can resolve two minor rendering issues: light fringing that can sometimes occur along the borders of downscaled objects, or a quality change in the last frame of an animation. Do not use this mode unless a rendering artefact is specifically observed and selecting this mode can be observed to resolve it: the increased memory usage can be very significant, and is not a cost that should be added for no reason.