Low resolution of view in Substance

Hi! When using a 4k screen, I am having a problem with the resolution of the 3D View section.

Not that textures would be bad resolution, or the render output, but the viewport itself of the painter (window in which I paint onto the model). Everything else is of correct resolution, all the thimbnails of materials, or the UI. It almost looks like the 3D view would be running at something like 420p. It's really bad, blurry, I can see pixels of edges. I can fix the pixelish edges by turning up temporal antialiasing but then its still very blurry, even more actually. Its very unusable. This started to be happening since I switched from educational license to the paid license. I tried reinstalling, but that did not help.

This issue seems like it's not happening when using a Full HD display. Using an FHD display is acutally sharper (even if at same size).

This issue is happening only in Substance Painter. No other 3D software is doing this. 

Thanks in advance for any help