A 4k at 28" you may not see any benefit over a 27" 1440p monitor. I use a 27" 1440p and I would have to be right up on the screen to see the pixels so other than losing performance in games I don't think there will be much difference (no personal experience with a 4k just fyi). I haven't seen a 1440p at 32" so I don't know if the pixel density is still good enough to where they are unnoticeable.
If it was me, I would be comparing a 27" 1440p vs a 32" 4k, I think that makes more sense when it comes to appropriate pixel densities. You have the horse power to drive 4k but at 28" I just don't know if it's worth it.